Ok, but not necessary - Trijicon ACOG 4x32 Flip Cap Set (Requires TA91 killFLASH)

I've had similar flip caps that I liked on my Leupold hunting rifles scopes so I gave these a try since the price was right. The flip caps work as expected. The front cap does requires the TA91 killFLASH in order to be mounted (which they tell you) and I am okay with. However, the killFLASH does not fit air tight into the ACOG, leaving a little wiggle room. To me, the purpose of a flip cap is to keep out dust and debris. With the killFLASH having the gap, it does help with debris, but not so much on the dust.
Pros: Super easy to install, just slide them on. The one for the eye piece is a little snug though.
Cons: None as far as the flip caps are concerned.

This review was written in the old system and had content requirements that are different than reviews written today.