For the safety of yourself and anyone who plays paintball with you or at your field you should not put an angled reg collar on a plain geo2.
On the geo2 the pcv is located inside the 90 degree fitting attached to the reg. it looks like a mini golf tee with a small hole through the middle. The purpose of this is to slow the purge of air when you degass the marker. Without the pcv your marker WILL fire a shot every time you degass. The pcv will not fit inside the macro fitting needed to use the angeld reg collar.
On the 2.1 they moved the location of the pcv to the top of the body where the reg attaches to the marker, allowing for the angled collar to be used.
Atlantic/Haze Geo 3