品牌简介：昭和21年初代社长山下宗一郎成立了山下工业研究所并创建了KOKEN（工研）套筒品牌昭和28年通过日本汽车配套部品（第333号）文件认定并相继通过日本整备航空机姳抦工厂和APA自卫队优良工厂认定，KOKEN（工研）套筒工具一直以优良的品质在日本军工，航空，汽车制造业有着很高的认知度。
 | 2400M
2405M
(mm) | 2400A
2405A
(inch) | D1
(mm) | D2
(mm) | H
(mm) | L
(mm) | | 3 | 1/8 | 5.2 | 11.2 | 3.0 | 22 | | 4 | 5/32 | 6.7 | 11.2 | 3.8 | 22 | | 4.5 |
| 7.1 | 11.2 | 4.2 | 22 | | 5 | 3/16 | 7.7 | 11.2 | 4.6 | 22 | | 5.5 |
| 8.3 | 11.2 | 5.0 | 22 |
| 7/32 | 8.8 | 11.2 | 5.0 | 22 | | 6 |
| 9.0 | 11.2 | 5.4 | 22 |
| 1/4 | 9.6 | 11.2 | 5.4 | 22 | | 7 | 9/32 | 10.2 | 11.2 | 6.1 | 22 | | 8 | 5/16 | 11.3 | 12.0 | 6.8 | 22 | | 9 | 11/32 | 13.0 | 12.0 | 7.5 | 22 | | 10 | 3/8 | 14.3 | 12.9 | 8.2 | 22 | | 11 | 7/16 | 16.0 | 14.3 | 8.9 | 22 | | 12 |
| 17.4 | 16.0 | 9.6 | 22 | | 13 | 1/2 | 18.0 | 16.4 | 10.3 | 22 | | 14 | 9/16 | 19.3 | 17.9 | 11.0 | 24 |
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