A 'ga tip' is a storage box made from reeds that is used to hold cooked sticky rice. It allows the rice to breath to release moisture and is ideal to carry sticky rice on picnics. Then there's the convenience, it's a nice way to carry a packed lunch, bags of meat and vegetables on the top, rice on the bottom, as the rice cools, it keeps the meat warm.
Above is my new fancy ga-tip, below is my old, not so fancy, one.The fancy one has a wooden stand on the lid too, so you can place the lid on a surface and place food in that, knowing that the lid is standing off the surface. Handy if you're in a field and can't trust the cleanliness of the table or bench that you're eating off.
If you store cooked sticky rice in a plastic box it can become clammy on the outside. In a 'ga-tip' it can breath, but if left too long will dry out too much. If that happens, simply steam it again to revive it.
A typical use for this is filled with sticky rice, with a bag of hard fried meat, such as the fried pork ribs, and sliced cold vegetables.