High-Quality MR16 GU5.3 / G4 Bi-Pin Lamp Holder. Standard G4 Bi-Pin base compatible with G4, G6.35, GY6.35, GX5.3, GU5.3, GZ4, MR11, and MR16 light bulbs. With its exceptional heat resistance and solid construction, you can trust that your light bulbs will be held securely and safely.