I have an older Denk II BV and wanted to buy a powerswitch unit. So I emailed Russ Lederman at Denkmeier optical and began to barrage him with questions. Russ replied within hours to each email and told me exactly what I needed. But first he asked for a complete description of what I had and how I wanted to use it so he did not sell me anything I did not need in case I had duplicate adapters. He also gave me a gratus upgrade on the OCS and he offered to inspect and collimate my BV unit and install the new Powerswitch at no charge if I sent him the BV. Wow...this is simply outstanding service and support on an already great product line. I had to share...!