The most common primer button used in chainsaws and clearing saws, used e.g. in several Efco, Jonsered, Husqarna, Stih, etc. machines. Attaches with "clips" to the hole in the case. e.g. in models:
Efco MT4100SP, MT4400, MT5200, MT440
Jonsered FC2145, CS2240, CS2240S, CS2153, CS2152
Husqvarna 543XP, 543XPG, 450 II, 450e, 450, 445e, 445, 440e, 440, 435e, 435
Stihl MS210, MS230, MS250
OEM Husqvarna 513789301, 503936601, 5137893-01 5039366-01, Stihl 41303506200 4130-350-6200, Walbro 188-512-1