Tire pressure gauge
 A pen-like pressure gauge has an elongated outer casing with a chuck, having a first portion accommodating a transparent inner casing and a second portion accommodating a piston member which is in sliding and sealing contact with the inner surface of the metallic outer casing and which is connected to a scale member extending into the inner casing. The graduation marks of the scale member can be viewed from a window of the outer casing through the transparent inner casing. 
G
G01L
inventional
Tien-Tsai
Huang