David Clark Kit, Boom Guide, pn. 12840G-01 

This item is the spare part for:

H10-30, H10-36, H10-56, H10-56N, H10-66, H3330, H3332, H3335, H3340, H3341, H3342, H3391, H3392, H7030, H7040, H7041, H7042, H7091, H8730, H8740, 12304G-07, 40685G-01, 40742G-01, 40772G-01, 40825G-01, 40835G-01, 40836G-01, 40859G-01