These Bubble Tubes are ideal for any Steampunk project. The pack contains 2 Bubble Tubes one is red flashing, whilst the other is green 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.