Grace USA - Roll Spring  (Pin) Holder Set - RSH-5  - Gunsmithing -  Roll Pin Holders - 5piece - Gunsmith Tools & Accessories The 1/16" Roll Spring (Pin) Holder is notched to clear most rifle platforms rear sights The 3.5mm is excellent for holding the pin that retains the breech block on Sig handguns The sizes are 1/16" (notched, 5/64", 3/32", 1/8", 3.5mm; Made from 5/16" Hex High Carbon 5160 Steel & Bainite heat treated for strength Single groove in grip section and laser marked for quick identification Made in the USA