Built for heavy-duty, field-ready performance, the Wilson Combat® 1911 ETM .45 ACP 8-Round Flat-Wire Spring & Follower Kit features maximum strength, flat wire MAX steel spring that’s up to 25% stronger than stock 1911 magazine springs for superior reliability with defensive and +P loads. The durable, heat-treated polymer follower ensures lasting corrosion, heat, and shock resistance. Compatible with #500, #500B, #500C, and #500BC magazines. Plus, this ETM Spring/Follower Kit will retrofit into all ETM 8-round .45 ACP magazines and will also convert 47 Series full size magazines to 7-round mags and 47 Series Compact magazines to 6-round mags.