These Bubble Tubes are ideal for any Steampunk project. The pack contains 2 Bubble Tubes one is blue non flashing, whilst the other is multi-colour flashing. The size of the tubes is 85mm long including brass fitting at the base. The brass fitting is 15mm in diameter. The pack comes complete with 2 x 9 volt battery terminals. You can run both off one battery or make 2 projects. An unusual addition to any project.