End treatment of aeroGAIN rod fibers is often important to assure high peak power operation. We offer the following end treatment options: Endsealing and cleaving (0 or 5 degrees angle) – the length of the endsealing (~100 µm) will not provide significant beam expansion.    Endcapping with 8x8 mm silica blocks providing beam expansion to reduce end facet intensity and the risk of end facet damage. Also, the beam expansion significantly improves the signal return loss even for a 0 degree angled facet. Soon to be released is a mechanical package option for well-controlled handling and cooling of the aeroGAIN rod fibers