that's what the locals in Tarakan calls this kind of sea shels. i went out on a bicycle ride last week which ends up on Amal beach, and eat some Kapah.
4 kilos of Kapah could be saute'd and became what you see on the above picture. it's cooked with some garlics and onions with lots of spices
and this is how we eat it, with some Buras (Borneo style rice cakes), 2 type of sambals (one made from garlic, chilli peppers and lime, while the other one is made from chilli, coconut milk, and some anchovy), and a big coconut to wash the thirst away... yumm..!!