I guess the subject says it all. Used for 50rds.
"One Shot Tactical Magazine Extension Tube with Right Hand Side Sling Mount, 12 Gauge
Scattergun Technologies™ magazine tube extensions are so tough they were selected for use by the U.S. Secret Service and the U.S. Border Patrol.
One Shot Magazine Extension Increases Magazine Capacity to 5 Rounds
Sling Mount for Right Hand Shooter, Mounts on Left Side
Includes an Extra-Power Magazine Spring for Improved Reliability
Includes a High-Visibility Follower for Improved Feeding and Visual Reference of Empty Magazine Tube
Fits Remington® M870 | 1100 | 1187 - 12 Gauge
Wave Washer Included
Only the strongest materials are used in constructing the magazine tube extensions to insure maximum resilience during rough usage. Each unit is shipped ready to install with our extra-power magazine spring and fully machined, neon green high-visibility follower."
Extension Tube, Right Hand, 1 Shot, 12 Gauge