XS Sights 24/7 Big Dot Tritium Express Sight Set for Walther PPS 9 & 40 Pistols, Includes Tritium Front / Rear Sights XS Sights 24/7 Big Dot Tritium Express Sight Set for Walther PPS 9 &amp; 40 Pistols, Includes Tritium Front / Rear Sights