a regular slide check will bleed air from the marker so that you can use a quick disconnect to take the remote off.
a pro connect sort of pops off and bleeds the air all at once through the use of a button.
many prefer the pro connect, as it is of higher quality and tends to need less maintenance.

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Proud Canadian Baller
Kit: A5, camo job, polished internals, 14" Smart Parts Progressive barrel. Borrowed Opsgear G36 stock. 24oz CO2 w/ remote and slide check. Neat homemade sling. MORE TO COME
Vents Goggles and Multicam