Seed and Berry
Device for measuring tire pressure and tire tread depth
 A safety device includes a compacted body accommodating a pressure gauge for determining the internal pressure of a tire and a unit for determining the degree of wear caused to the tread of a tire, which includes a slide ruler to measure the depth of the indentations in the tread of the tire. The slide ruler is received in a slide groove provided in the body of the device and associated with graduation marks which show the depth of the indent in the tire tread when the slide ruler extends thereinto. 
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G01L G01L G01B
inventional inventional inventional
Tien-Tsai
Huang