Precision machined with maximum strength Four 6” long mil-spec Picatinny rails with 14 slots each for versatile accessory applications Clever rail system locking design includes lower connecting walls mating with upper channels to achieve the most solid and secure fit- Lower quad-rail system to secure barrel Upper quad-rail system to secure gas tube Simple and friendly installation, no gunsmith required Great zero-retention capability for all accessories installed on the rails Intensively tested by field experts under extreme heat and sub-zero temperature and demonstrates most satisfactory performance Specially designed groove rail top for optimal viewing through front sight Fits Model 47 and variants with oversized barrel and rear sight block Hard anodized finish for wear resistance UTG rubber rail guards included for great comfort and protection