This tank is designed to be direct replacement to fit into the ULTRA FLASH with no modifications to the airframe.  The main tank has 1 standard size 1/8" ID vent and an 1/8" ID Jet Tech O-ring style fuel fitting, pictured below. This Fuselage tank carries 78 oz.  

The tanks come fully assembled and pressure tested with Jet Tech O-ring style fuel and vent fittings installed but does not include a clunk.  Clunks may be ordered separately on the "fuel fittings"  page.