These window jambs were designed and created in collaboration with Tern Overland in order to create a perfectly fitting window jamb for their Arctic Tern windows. The kit consists of two pieces, an inner and outer trim ring. Please watch the video below if you're confused about the difference between the inner, outer, and the full kit.

Outer Ring Thickness: The different sizes are to accommodate differences in individual builds. Depending on what you do for framing, insulation, and wall material, the measurement from the window to your finished wall will vary. We typically use the 2.1" rings in our Sprinter & Promaster builds, and the 2.8" rings in our Transit builds. We use 3/4" framing with 1/4" walls. If your material is thicker or you'll be using lots of insulation, we recommend the 2.8". It's always better to err on the side of more material since you'll be able to trim it down to fit perfectly.

1.4" Recommended only for builds with minimal insulation & framing. 

NOTE: ONLY COMPATIBLE WITH ARCTIC TERN WINDOWS. Visit their website to order windows. Important: Specify the 35-44mm thickness when ordering from them.