THIS LITTLE BUGGER TELLS THE NEUTRAL LIGHT WHEN ITS TIME TO LIGHT UP. AND EVEN IF YOU DON'T HAVE A NEUTRAL LIGHT , ITS NEEDED TO KEEP OIL FROM GUSHING OUT WHEN THE ENGINE IS RUNNING. Well this is 10mm diameter and total overall length end to end is 33mm. Length of the plastic part is 21mm not counting anything brass. 71H @ *NEUTRAL CONTACT/SWITCH HOLDING_PLATE 35755-001-020 1/21M (256F)(C70_80/81)_(I_THINK_THIS_CAN_WORK_LIKE_A_SPRING_TO_KEEP_PRESSURE_ON_THE_NEW_TYPE_CONTACT AGAINST THE SHIFT DRUM CONTACT PAD) CLICK ON THE PICTURE TO THE LEFT TO SEE ALL THE MODELS THIS FITS 256F @ *O-RING NEUTRAL CONTACT 7X1.6 37551-001-000 1/20M (R2216)O-RING (7x1.6) ATC70 K0-K1, C70 K1, C70M, CA100, CA102, CA105T, CA110, CA200, CL70 K0-K3, CL90, CM90, CT200, CT70 K1-77, CT70H HK1, CT90 K0, S65, S90, SL70 K0-K1, SL90, ST90 K0-K2, XL70 K0-76 R2216