TheraBulb bulbs can be used to replace existing bulbs in some near infrared lamps. Here's how to find out if TheraBulb bulbs are compatible with your lamp:

Base/ Socket:  TheraBulb bulbs have size E26 (120V) and E27 (240V) bases, which fit size E26 and E27 sockets, respectively. These are screw-type bases. If your lamp does not have a screw-type socket, a TheraBulb bulb cannot be operated in it.

Size:  Dimensions for TheraBulb bulbs are as follows:

• Near Infrared Bulb Small Form - 150 Watt: 3.75 inches diameter x 5.25 inches height

• Near Infrared Bulb - 250 Watt:  5.25 inches diameter x 6.5 inches height

There are several lamps models that have original bulbs that are longer than 6.5 inches.  As a result, you will need a bulb extender to operate a TheraBulb in these lamps. The photo shows one of the lamps that will operate a TheraBulb bulb with an extender.