Type of lead release/catch

Can anyone point me in the right direction to find a lead with a carabiner type catch? What I am looking for is a catch that is the standard "P" shape but instead of a spring loaded pull back lever it has a push down spring to release (difficult to describe but if you have seen one you will know what i mean). Any ideas anyone?

Is this what you mean
http://www.4activedogs.co.uk/knot-a-...ner-1198-p.asp

I have never seen them on the standard P...but the Lupine leads have the sping clips (so you can just push against the collar and it catches....

Hardware stores have a variety of things you could use to replace the snap on a leash including small carabiners. Look near the nuts and bolts. I have ones that you just push in and ones you lock with a thread.

I used them to make up short lengths of chain to use as tie downs. Very useful at times.