2444 x 1. A new Blank Seat Frame Base made to XK120 seat base spec. but come undrilled and without seat adjuster lever fittings (to come as a kit later). You may then drill the pivot holes to suit a standard or custom Tilting Back. An often missing part that can be difficult and expensive to replace, copied from  an original. Original Ref. BD3252. BD3253

NOTE : As this will come as a blank you may fit it as you wish. It can also be narrowed by 1inch to make it into an XK140 width Base Frame

There are then options to fit :

Standard XK120 Runners (2440A)

or XK140 / XK150 Seat Runners (2440B)

Aftermarket Seat Runners (SE424)