I have a number of cameras an accessories with ARCA type plates, so finding a decent quick release unit was important for me. Initially I used cheap Chinese screw adapters, but I felt there had to be a better way. Manfrotto released the MSQ6 in 2013 but I only heard about it last year (Well, I do live in France!) Strangely it's not available as an accessory here - so I ordered mine from the UK. The unit is far from cheap (at around £100) but it is sturdy and well designed. Contrary to what can be found on the MANFROTTO site, it fits a large number of ball heads - I have it on the 492RC, the XPRO and a 468MG (this latter for which an round adapter disc is included in the box with the unit) There's not alot to be said about the action - clip the plate into the unit and tighten the knob to hold. To release the plate, undo the knob a little, then press on the red plastic button. A recent forum thread (and the purchase of a 'used' XPRO) got me thinking, and I may have found a cure for the people who's L plates seem to get stuck in this unit - it seems the spring for the moving plate was originally a small piece of silicon tube - this has now been replaced by a redesigned sliding plate and metal spring. This is available for order (16.70€) from MANFROTTOSPARES.COM and since replacing the springs/plates on the two I own, I no longer seem to have L plates that can't be released.