Drip feed oilers are perhaps the most popular method of automatic oil lubrication. The lubricant feed rate can be set by the operator by merely turning the needle valve and viewing the drip rate in the flow sight. Oil flow can be stopped simply by shutting the valve.
A cam-lock valve flow sight is also available with drip oilers as an alternative method for precise metering applications. They have a durable polycarbonate flow sight, which is a major improvement over the breakable glass sights currently used in other drip oilers. These valves may be purchased separately.