O-Rings

JIS B2401

JIS B2401 O-Rings follow the Japanese Industrial Standard for metric O-ring sizes, including P, G, S, and V series. Used across a wide range of hydraulic, pneumatic, and industrial sealing applications, these O-rings offer reliable performance and compatibility with global systems. Available in various materials to meet specific temperature, pressure, and chemical resistance needs.

Dimension table

Technical diagram showing piston and rod applications for JIS B2401-1 P series, with labeled measurements for diameter, width, and gaps.
Technical diagram showing cross-sectional views and details of cylindrical surface grooves, including static and groove dimensions, with annotations of pressure types and groove configurations.
Part No. Dimensions of O-Rings
（Unit：mm)		 Groove dimensions for dynamic &
static in cylindrical surface （Unit：mm)		 Groove dimensions for static on flat-surface
（Unit：mm)
W d D d D G＋0.25
0		 External pressure Internal pressure G＋
0.25
0		 H±
0.05		 R
(max）		 E
(max）
Back-up ring d D
0 1 2
P 3 1.9±0.08 2.8±0.14 6.6 3 0
-0.05		 6 +0.05
0		 2.5 3.9 5.4 3 6.2 2.5 1.4 0.4 0.05
4 3.8±0.14 7.6 4 7 4 7.2
5 4.8±0.15 8.6 5 8 5 8.2
6 5.8±0.15 9.6 6 9 6 9.2
7 6.8±0.16 10.6 7 10 7 10.2
8 7.8±0.16 11.6 8 11 8 11.2
9 8.8±0.17 12.6 9 12 9 12.2
10 9.8±0.17 13.6 10 13 10 13.2
P 10A 2.4±0.09 9.8±0.17 14.6 10 0
-0.06		 14 +0.06
0		 3.2 4.4 6 10 14 3.2 1.8 0.4 0.05
11 10.8±0.18 15.6 11 15 11 15
11.2 11.0±0.18 15.8 11.2 15.2 11.2 15.2
12 11.8±0.19 16.6 12 16 12 16
12.5 12.3±0.19 17.1 12.5 16.5 12.5 16.5
14 13.8±0.19 18.6 14 18 14 18
15 14.8±0.20 19.6 15 19 15 19
16 15.8±0.20 20.6 16 20 16 20
18 17.8±0.21 22.6 18 22 18 22
20 19.8±0.22 24.6 20 24 20 24
21 20.8±0.23 25.6 21 25 21 25
22 21.8±0.24 26.6 22 26 22 26
P 22A 3.5±0.10 21.7±0.24 28.7 22 0
-0.08		 28 +0.08
0		 4.7 6 7.8 22 28 4.7 2.7 0.7 0.08
22.4 22.1±0.24 29.1 22.4 28.4 22.4 28.4
24 23.7±0.24 30.7 24 30 24 30
25 24.7±0.25 31.7 25 31 25 31
25.5 25.2±0.25 32.2 25.5 31.5 25.5 31.5
26 25.7±0.26 32.7 26 32 26 32
28 27.7±0.28 34.7 28 34 28 34
29 28.7±0.29 35.7 29 35 29 35
29.5 29.2±0.29 36.2 29.5 35.5 29.5 35.5
30 29.7±0.29 36.7 30 36 30 36
31 30.7±0.30 37.7 31 37 31 37
31.5 31.2±0.31 38.2 31.5 37.5 31.5 37.5
32 31.7±0.31 38.7 32 38 32 38
34 33.7±0.33 40.7 34 40 34 40
35 34.7±0.34 41.7 35 41 35 41
35.5 35.2±0.34 42.2 35.5 41.5 35.5 41.5
36 35.7±0.34 42.7 36 42 36 42
38 37.7±0.37 44.7 38 44 38 44
39 38.7±0.37 45.7 39 45 39 45
40 39.7±0.37 46.7 40 46 40 46
41 40.7±0.38 47.7 41 47 41 47
42 41.7±0.39 48.7 42 48 42 48
44 43.7±0.41 50.7 44 50 44 50
45 44.7±0.41 51.7 45 51 45 51
46 45.7±0.42 52.7 46 52 46 52
48 47.7±0.44 54.7 48 54 48 54
49 48.7±0.45 55.7 49 55 49 55
50 49.7±0.45 56.7 50 56 50 56
P 48A 5.7±0.13 47.6±0.44 59 48 0
-0.1		 58 +0.1
0		 7.5 9 11.5 48 58 7.5 4.6 0.8 0.1
50A 49.6±0.45 61 50 60 50 60
52 51.6±0.47 63 52 62 52 62
53 52.6±0.48 64 53 63 53 63
55 54.6±0.49 66 55 65 55 65
56 55.6±0.50 67 56 66 56 66
58 57.6±0.52 69 58 68 58 68
60 59.6±0.53 71 60 70 60 70
62 61.6±0.55 73 62 72 62 72
63 62.6±0.56 74 63 73 63 73
65 64.6±0.57 76 65 75 65 75
67 66.6±0.59 78 67 77 67 77
70 69.6±0.61 81 70 80 70 80
71 70.6±0.62 82 71 81 71 81
75 74.6±0.65 86 75 85 75 85
80 79.6±0.69 91 80 90 80 90
85 84.6±0.73 96 85 95 85 95
90 89.6±0.77 101 90 100 90 100
95 94.6±0.81 106 95 105 95 105
100 99.6±0.84 111 100 110 100 110
102 101.6±0.85 113 102 112 102 112
105 104.6±0.87 116 105 115 105 115
110 109.6±0.91 121 110 120 110 120
112 111.6±0.92 123 112 122 112 122
115 114.6±0.94 126 115 125 115 125
120 119.6±0.98 131 120 130 120 130
125 124.6±1.01 136 125 135 125 135
130 129.6±1.05 141 130 140 130 140
132 131.6±1.06 143 132 142 132 142
135 134.6±1.09 146 135 145 135 145
140 139.6±1.12 151 140 150 140 150
145 144.6±1.16 156 145 155 145 155
150 149.6±1.19 161 150 160 150 160
P 150A 8.4±0.15 149.5±1.19 166.3 150 0
-0.1		 165 +0.1
0		 11 13 17 150 165 11 6.9 0.8 0.12
155 154.5±1.23 171.3 155 170 155 170
160 159.5±1.26 176.3 160 175 160 175
165 164.5±1.30 181.3 165 180 165 180
170 169.5±1.33 186.3 170 185 170 185
175 174.5±1.37 191.3 175 190 175 190
180 179.5±1.40 196.3 180 195 180 195
185 184.5±1.44 201.3 185 200 185 200
190 189.5±1.48 206.3 190 205 190 205
195 194.5±1.51 211.3 195 210 195 210
P 200 8.4±0.15 199.5±1.55 216.3 200 0
-0.1		 215 +0.1
0		 11 13 17 200 215 11 6.9 0.8 0.12
205 204.5±1.58 221.3 205 220 205 220
209 208.5±1.61 225.3 209 224 209 224
210 209.5±1.62 226.3 210 225 210 225
215 214.5±1.65 231.3 215 230 215 230
220 219.5±1.68 236.3 220 235 220 235
225 224.5±1.71 241.3 225 240 225 240
230 229.5±1.75 246.3 230 245 230 245
235 234.5±1.78 251.3 235 250 235 250
240 239.5±1.81 256.3 240 255 240 255
245 244.5±1.84 261.3 245 260 245 260
250 249.5±1.88 266.3 250 265 250 265
255 254.5±1.91 271.3 255 270 255 270
260 259.5±1.94 276.3 260 275 260 275
265 264.5±1.97 281.3 265 280 265 280
270 269.5±2.01 286.3 270 285 270 285
275 274.5±2.04 291.3 275 290 275 290
280 279.5±2.07 296.3 280 295 280 295
285 284.5±2.10 301.3 285 300 285 300
290 289.5±2.14 306.3 290 305 290 305
295 294.5±2.17 311.3 295 310 295 310
300 299.5±2.20 316.3 300 315 300 315
315 314.5±2.30 331.3 315 330 315 330
320 319.5±2.33 336.3 320 335 320 335
335 334.5±2.42 351.3 335 350 335 350
340 339.5±2.45 356.3 340 355 340 355
355 354.5±2.54 371.3 355 370 355 370
360 359.5±2.57 376.3 360 375 360 375
375 374.5±2.67 391.3 375 390 375 390
385 384.5±2.73 401.3 385 400 385 400
400 399.5±2.82 416.3 400 415 400 415
Part No. Dimensions of O-Rings
（Unit：mm)		 Groove dimensions for dynamic &
static in cylindrical surface （Unit：mm)		 Groove dimensions for static on flat-surface
（Unit：mm)
W d D d D G＋0.25
0		 External pressure Internal pressure G＋
0.25
0		 H±
0.05		 R
(max）		 E
(max）
Back-up ring d D
0 1 2
G 25 3.1±0.10 24.4±0.25 30.6 25 0
-0.1		 30 +0.1 0 4.1 5.6 7.3 25 30 4.1 2.4 0.7 0.08
30 29.4±0.29 35.6 30 35 30 35
35 34.4±0.33 40.6 35 40 35 40
40 39.4±0.37 45.6 40 45 40 45
45 44.4±0.41 50.6 45 50 45 50
50 49.4±0.45 55.6 50 55 50 55
55 54.4±0.49 60.6 55 60 55 60
60 59.4±0.53 65.6 60 65 60 65
65 64.4±0.57 70.6 65 70 65 70
70 69.4±0.61 75.6 70 75 70 75
75 74.4±0.65 80.6 75 80 75 80
80 79.4±0.69 85.6 80 85 80 85
85 84.4±0.73 90.6 85 90 85 90
90 89.4±0.77 95.6 90 95 90 95
95 94.4±0.81 100.6 95 100 95 100
100 99.4±0.85 105.6 100 105 100 105
105 104.4±0.87 110.6 105 110 105 110
110 109.4±0.91 115.6 110 115 110 115
115 114.4±0.94 120.6 115 120 115 120
120 119.4±0.98 125.6 120 125 120 125
125 124.4±1.01 130.6 125 130 125 130
130 129.4±1.05 135.6 130 135 130 135
135 134.4±1.08 140.6 135 140 135 140
140 139.4±1.12 145.6 140 145 140 145
145 144.4±1.16 150.6 145 150 145 150
G 150 5.7±0.13 149.3±1.19 160.7 150 0
-0.1		 160 +0.1 0 7.5 9 11.5 150 160 7.5 4.6 0.8 0.1
155 154.3±1.23 165.7 155 165 155 165
160 159.3±1.26 170.7 160 170 160 170
165 164.3±1.30 175.7 165 175 165 175
170 169.3±1.33 180.7 170 180 170 180
175 174.3±1.37 185.7 175 185 175 185
180 179.3±1.40 190.7 180 190 180 190
185 184.3±1.44 195.7 185 195 185 195
190 189.3±1.47 200.7 190 200 190 200
195 194.3±1.51 205.7 195 205 195 205
200 199.3±1.55 210.7 200 210 200 210
210 209.3±1.61 220.7 210 220 210 220
220 219.3±1.68 230.7 220 230 220 230
230 229.3±1.73 240.7 230 240 230 240
240 239.3±1.81 250.7 240 250 240 250
250 249.3±1.88 260.7 250 260 250 260
260 259.3±1.94 270.7 260 270 260 270
270 269.3±2.01 280.7 270 280 270 280
280 279.3±2.07 290.7 280 290 280 290
290 289.3±2.14 300.7 290 300 290 300
300 299.3±2.20 310.7 300 310 300 310