The Aqua-Pure 5605831 is the correct replacement UV lamp for the following filter systems:
The Aqua-Pure 5605831 Replacement APUV1 Bulb is a replacement UV lamp for the Aqua-Pure APUV1 UV Water Filtration System. The APUV1 bulb is a high output, low pressure mercury vapor lamp with a high isolation design. This UV bulb can be changed quickly and easily, without having to disconnect the water flow. Aqua-Pure recommends that this UV lamp be replaced every 12 months to achieve the best filtration results.
Aqua-Pure 5605831 Replacement APUV1 Bulb specifications: