These pin lock disconnects are the ones that fit onto Coca Cola Kegs.
They are called pin lock disconnects because they interlock with the posts on the kegs using 2 or 3 pins. So to attach these to the kegs you push down and then twist the disconnect to engage the collet.
The are less popular than ball lock fittings but still quite common in the home brewing industry.
Black/Liquid disconnect with barb to suit Pin Lock Kegs
With regards to beer line to be used with these disconnects we would recommend using either:
4mm ID x 8mm EVABarrier Beer Line
or
5mm ID x 8mm EVABarrier Beer Line