FN 509M 9mm 17rd Magazine Sleeve (20-100355)

Made from durable polymer, the factory original FN 509M 9mm 17rd Magazine Sleeve (20-100355) can be placed on any compatible 509 17 round mag, allowing it to fit the Midsize models. This sleeve allows the use of a increased capacity magazine and extends the grip surface of the FN America 509 Midsize model pistols.