The WS 8J Kit comes supplied with a pistol grip & boom adaptor, both of which have a female 3/8” brass insert.
In order to mount to a tripod, you will need a 3/8” Hot Shoe Adaptor. This has a male 3/8” thread and a cold shoe with built-in female 1/4” thread (see underside pictured in the link below), allowing you to attach the whole solution to a standard tripod.
Hot Shoe 3/8"Adaptor
Order Code: 037302