'French-style' Sheaths - These are the standard, plain 'French-style' 1/2cc slit goat sheaths. The 1/2cc wick and powder straws are seated into the interior tip of the sheath when it is fully affixed to the gun.
'Insert-style' Sheaths - This style of sheath uses a sliding insert within the barrel of the sheath that seats the straw snugly, wheather 1/2cc or 1/4cc, as the sheath is being slid onto the gun. Available in either a slit version (green insert) or in an unslit version (blue inserts). The All-2-Mate (#463250) A.I. gun requires the use of a slit sheath whereas the Quicklock Classic (#17350/0000) A.I. gun can use either the slit or unslit sheaths.
APEX Goat Sheaths - Another option that works very well is the APEX version. The apex tip on these sheaths tapers down to a small diameter allowing dispensing at the cervix. The interior portion of the apex design also acts as a straw seating device, so both 1/2cc and 1/4cc straws can be used with it.