Adjustable Desgin: There are 4 settings on the Pic rail mount and the spring detent adjustment is very handy which allows you to easily adjust the distance of the brass catcher to the ejection port..Low Profile & Quickly Detachable: The mounting piece that goes on the picatinny rail is very low profile and fits easily under the scope. The quick disconnect is easy to use and manipulate..Quality Construction: The thickened nylon ensures it will not melt when ejected. There is a zipper in the bottom of the bag so you can empty it without removing the catcher from your rifle..Larger Opening: 5"x2.75" Opening is quite large and does not interfere with the ejection of the spent brass case. Holds 100 rounds of .223 brass, t can hold a large number of shells before it needs to be emptied. Ideal for reloaders..This Feyachi brass catch is versatile enough to allow for mounting to almost any rifle with a pic rail. Great for anyone reusing brass or wanting to keep outdoor ranges clean. Includes two pic rail mounts for easily and quickly transfer this catcher to another firearm.