The J301/J is a flat slip-on jumper designed for use with Magnum series terminal blocks, specifically compatible with single and double row configurations. This jumper features a 0.250" blade width and is engineered to provide reliable electrical connections between adjacent terminal positions. The flat slip-on design allows for easy installation directly over the terminal barriers without requiring tools or fasteners. The J301/J is commonly used in applications requiring quick interconnections between terminal block positions, offering a convenient solution for circuit modifications and temporary connections in industrial control panels and electrical distribution systems.