speed ring sight

base junction; rotary collector ring (box); rotary base junction (of a tank); rotary connection; slip ring; traverse rotary base junction

life ring (ring buoy)

fixed ring (of a gyroscopic sight)

supersonic speed (exceeds speed of sound / Mach 1)

variable-speed with speed control

instantaneous vertical speed indicator / instantaneous vertical-speed indicator (IVSI)

Nr gauge (Nr = speed of rotation) / rotor speed sensor

Motor PWM speed separated from PID speed

front sight (fore / muzzle sight)

sight, to take a (careful) sight

day-sight (day sight)

modular integrated display and sight helmet (Modular Integrated Display-And-Sight Helmet)

base ring

breech ring (of firearm)

D-ring

gun ring

jet ring

retaining ring

safety-pin ring

stator ring

stiffener ring

X ring

defense ring

power-slip ring

slinger ring

slip ring

slip-ring box

slip-ring terminal

fire extinguishing ring

sprocket ring

tie-down ring

trunnion ring