Ed Brown Mainspring Housings are fully machined from solid steel. The sharp checkering is machine cut into each housing with expert precision then finished by hand. Custom Snakeskin housings have scales instead of checkering for a unique look. Chain link housings use a proprietary grip pattern that provides good traction for the hand, without the sharp edges of checkering. The Flat Housing is the standard 1911 design for the clean, classic look. Drop-in fit will work with virtually any 1911 style handgun. Notes: Will not fit Para-Ordnance Models P-10, 12, 13 or STI/SVI Infinity