link here
http://www.manortronics-force-gauges.com/Astro.html
Astro fix nms - by manortronincs - this is a great cheap way to locate objects with your dobsonian -or to align your mount for astrophotogrpahy..item is brand new & comes with re-chargeable battery & charger, instructions included
$140 + post (express or reg'd both $8)