Customizable body size Each GLOCK Gen5 comes with beavertail backstraps in two sizes. The backstrap frame enables the users to change the circumference of your grip to fit their specific hand size. Gen4 RTF - Rough textured body The Gen4 demonstrated rough textured frame floor is current to the Gen5 https://mariobdbbx.blogsvila.com/30830017/a-review-of-glock-17