Sometimes referred to as a loft catch, these used mainly on drop-down loft hatches and other smaller cupboards because of the hook keep. Pushing the door/trap will release the catch and the door will spring open. Push it back to engage the latch. If you need this kind of action on a normal opening door or panel, then check out the Mini Automatic Catch instead.
Priced each as shown
I used the latch on my 25 mm thick MDF Airing Cupboard Doors - works magnificently to push shut/open