I use this bottle sealer for customized 5oz specialty oil cans. It took me only 2 tries to get it right, it's easy to handle. I sealed 1 bottle and put it out in the Texas sun, the bottle on its side for approx 2 weeks. There was no oil leak, I than squeezed the bottle as hard as I could to see if the seal blows off or breaks, nothing.Just make sure that your handheld unit comes close to the bottle cap size, in my case 24mm bottle cap and 10-50mm handheld unit. Most devices have a 10-100mm handheld unit with is not so good for small bottle caps.