This is a Mesa Tactical Side Saddle, model 90890.
SureShell Aluminum Shotshell Carriers with Rail are machined from 6061-T6 aluminum and use Mesa Tactical's innovative rubber friction retention system to firmly and reliable hold shells in place until needed.
Features:
SureShell Carrier
8-Shell
12 Gauge
6061-T6 Aluminum
Picatinny Rail