Coherent Avia laser SHG LBO Crystal in oven. 

These LBO crystals average around 2.65-2.78mm tall x 2.25mm wide by 20mm long. These crystals appear unused. I installed them out of the included membrane box. 

Most of the photos are of others I have had in the past, I don't have any connect to the bottom base plate. I will include the bottom part of the base plate as shown in the first photo that came from a different unit so alignment will be tough..

LBO's like this require slow heating or cooling down over about 1/2 hour to the required temperature to resist cracking the crystal.