Because 921 bulb is similar to t10 bulb, they don’t know clearly what is a 921 bulb.

I would like to explain you 921 bulb as below.

921 bulb is the same base of t10 bulb, which is w2.1*9.5d.

921 bulbs are all 12v 16w.

In my factory, we also producing 921 bulb in LED type.

All of our 921 bulbs are all very long life time.

I will show you best 921 bulb as below and you can check it.

Welcome all customers come to talk with us what is a 921 bulb at any time.