The Yak Attack Screwball 1.0 in. Ball with MightyBolts is compatible with the Wilderness Systems SlideTrax Accessory System as well as other track systems.
I used this to mount my Lowrance Elite 4 DSI Sonar/GPS fishfinder. Very nice.
Pretty cheap...will split open if you barely over tighten the least little but. Its too loose if you dpon't. I am on #3 now and won't buy another.
The screwball mount with mighty bolts works great with tehGT90 Track system. Also tried the cell blok battery system but found the total weight to cause the Kayak to list. and opted for the track screwball to do the job much better.
Worked great with GT90 track