Similar to the ones in the picture. They are 3/8 x 2 Thinwall tubes with 3/8 poly plug red push in caps I can order the whole kit, but really only need the vials... and maybe a vent liner
1- screw on caps and he has several colors to choose from.
2- taper ends on inside of tube instead of flat. All the powder seems to come out a little easier as opposed to the flat ones which some granules of powder always wants to stick to the bottom.
3- Very reasonably priced.