The R1-4 Open is a sub-miniature imperial ball bearing designed for applications where even the slightest mechanical resistance must be eliminated. By omitting shields and seals, this "Open" configuration offers the lowest possible starting and running torque. It is specifically engineered for high-speed, light-load mechanisms housed in clean-room environments or enclosed systems where external lubrication is provided. With a 1/8-inch bore, the R1-4 Open allows for effortless free-spinning, making it a critical component for high-frequency oscillators and sensitive measuring instruments.