it appears that it is a nozzle tester from what I've seen online https://www.google.com/#hl=en&sclient=psy-ab&q=Bosch%200681200502&pbx=1&oq=&aq=&aqi=&aql=&gs_sm=&gs_upl=&bav=on.2,or.r_gc.r_pw.r_cp.r_qf.,cf.osb&fp=e497b0ef37f63d8f&biw=1184&bih=546&pf=p&pdl=500