Losi Extra Rigid Ball Cups (LOSA6016) pack of 16, you will also need 1 pack of HPI 4.3 Ball Studs of 10mm and 2 of 13mm. I could only get the 13mm long ones (75116) but will probably just cut down any that need to be shorter.
Got mine from RCLazy in Bournemouth, top fellas as well.
