This unit is a very common UV nail polish curing unit available cheaply on ebay. It uses four 9W UVA tubes like the ones found in insect traps and UV exposure units. The unit has the option of continuous or timed operation with a fixed time of two minutes. I experimentally exposed a piece of photo sensitive PCB laminate with a transparency and piece of picture-frame glass to keep it all flat, and it exposed fully in the two minute cycle. This makes it one of the cheapest PCB exposure units available.
Inside there is a single PCB with a microcontroller based timer and an electronic ballast that uses a single drive circuit, but has a choke for each tube. For the money this unit is very impressive.