A bipolar transistor comprises at least first and second connected emitter-base junctions having, respectively, different first and second EB junction depths, and a buried layer collector having a greater third depth. Each therapy station includes a hydrotherapy assembly and each such assembly includes a plurality of fluid jets in the floor or sidewall of the enclosure and a fluid inlet through the floor or sidewall of the enclosure. A honeycomb catalyst having the catalyst carried thereon is also disclosed.