Rosco 13686 Sandwich-Style Pattern Holder - B Size - ETC S4
Details
Steel/Metal Gobos only
B Size (86mm x 64.5mm image area)
Maximum gobo thickness is 15mil
For use in:
ETC Source Four, Source Four Zoom
Rosco manufactures gobos holders for use in some of the most popular lighting fixtures. However, given the incredibly wide range of fixtures available around the world, there are many instances where Rosco does not have a holder available. In that instance, you should contact the manufacturer of the specific fixture for their recommendations. Consult the fixture specifications page to determine what size gobo is required for your luminaire and whether one of Rosco's gobo holders will work.
Rosco 13686 Sandwich-Style Pattern Holder - B Size - ETC S4 (Rosco 250136860000) 
Customer service via phone call was excellent and ordering products online was very easy.
No complaints
Found a hard to find part and it was still affordable. The payment process was a bit of a problem, the system either wasn't working properly or it needs a bit of clarification on the instructions. I did get it paid for and the delivery was fast. Overall satisfied with this purchase.