B66-275 GRAVITY INCLINOMETER. Deck Patent. The inclinometers patented by Thomas Deck of Toledo and manufactured by Deck's Gravity Level Co. have an unusually elaborate balancing mechanism to support the needle that tends to make it very sensitive but not very practical. This is the 24" version. As with many examples, the needle tends to stick, but otherwise a clean example of a very uncommon and collectible inclinometer. If you want to spring for an absolutely mint example in the original box, see Lot 575. From the collection of David Jeffers. Good+ 200-400