Well, i ordered some closed covers from the link below for the Thumper from Wizard and guess what... they are too small, by about 2mm all around - at a squeeze the Thumper would go in but not without putting quite a bend in the sides of the covers, and the possibility of cracking the plastic
[url="http://www.guitarpartsresource.com/bpickup_covers.htm"]http://www.guitarpartsresource.com/bpickup_covers.htm[/url]
the Thumper did however fit perfectly into the normal open covers of my 1977 Aria II Precise Bass where it now resides
Oh well, nothing ventured....
Fishman