Our clear acrylic gun stands are *sold separately* (NOT BY THE PAIR) and can be used in different height combinations to accommodate different style guns. Usually a shorter one is put in the back. Our sword stands (SWS) can also be used in conjunction with these gun stands, for the barrel end of the gun, to achieve a desired height. These will not work with a side by side shotgun. The opening is approximately 1.375 inches; at the top. SOLD INDIVIDUALLY. If a wider top is needed check out our wide top version here: https://www.amazon.com/dp/B01N2BIVN5