BA15D to GX4.0 or GU4.0 Converter Adapter Product Code: 23543 Price: $3.99 Volume Price   Adapter / Converter BA15D to GU4.0 or GX4.0 Adapter Socket Converter Qty: Warranty: 3 Months Have you used this item? Be the first to Write a Review   BA15D to GX4.0 or GU4.0 Converter. Use this converter to convert your old BA15D light bulb fixture to a GX4.0 or GU4.0 socket so then you can use a G4, JC, MR11 or MR16 LED Light bulb or standard incandescent light bulb. This LED converter/adapter is designed to be durable and is compatible with most G4 two prong bulbs. Approximate size is 1.22in x .66in.