It belongs to UR type wire conductors butt splice, which changed complicated traditional cable wire twist and soldering connection method. Insert three conductors separately into three ports without stripping conductors insulation; Crimp or squeeze the yellow button onto the inside three conductors with a pliers (here is not included.); Now you finished it! Gel-filled inside design promises an air-tight environment for conductors. and exquisitely design offer - function to protect the connection against air and moisture. Product Name: UR Connector Model: K3 Type: 3 Port, Single Blade; Applicability: To Connect two Telephone Wires, Data Signal Cables, and Other Conductors. Suitable Wire Conductor Diameter: 0.4mm-0.9mm Material: Plastic Casing, Gel-Filled Inside Main Color: Clear, Red Size (Each One): 19 x 12 x 8.4mm / 0.7 inch x 0.5 inch x 0.33 inch (L x W x H) Total Weight: 530g Package Content: 550 x UR Butt Splice Connector Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.