Attached is a PIX showing (CW from top left) the: >ionizer filament >Oven filaments (STD oven) >standard oven assy >high perm oven assy The HiPerf oven filament is the sealed spiral wound tube on the face of the oven. The posts on the top edge of the ovens is the connection to burn a hole in the burst disc to release the Cesium once the tube is pumped down.. Cheers, Corby