fuckin eh is right - the type of cap is a regular pop bottle cap 2L or a smaller bottle - the caps are the same size anyways. To make nice holes in it get a medium pair of scissors with a pointy tip and put the cap on the ground hollow side down and just rest the tip on the cap and push thru it when you think its positioned - after the scissors are in the cap start twisting the scissors to round out a hole. Be sure not to push the scissors in too far, or else your hole will be too big. Instead of 2 tubes/straws, I use one, and have just a smaller hole beside that without any tubes in it - works the same. Also, make sure you dont make the two holes too close to the edge of the cap ( make them about a half cm in ) because you still have to screww the cap on the lightbulb - hope it helps