Airless Pump Bottles for Cosmetics - 15ml (0.5oz), 30ml (1oz) & 50ml (1.7oz) Refillable Travel Size Containers for Cream, Serum, Lotion, Oil & Gel - Leak-Proof Dispenser for Skincare & Beauty Products - Perfect for Home Use, Travel & Salon Professional Kits

I ordered all three sizes of these Bottles, and they work great. They are shipped in two pieces: the container and the pump head. To assemble, you fill the container with your potion, then push the head into the bottom with some force (don't overfill). It will snap into place and form an excellent seal.My only problem is that because they are so small, you run out of the filler quite quickly, so naturally, you'd probably like to refill after washing and sterilizing. That great seal I mentioned above makes it next to impossible to get them open without damaging the pump head, so you may just throw it away. With some effort, I was able to remove one by pulling the base of the head to one side and slipping my fingernail in there long enough to get some leverage. I suspect that doing so may affect the integrity of the seal over time, and this sanitary issue may be why it's perhaps intentionally difficult. In truth, they are not that expensive, so if they are single use, it's not a tragedy.It would have been nice if the seller had included instructions informing me a) whether the bottles can be reused and b) if so, how to do it.