This kit extends the vent cap away from the exterior wall which is needed when mounting the vent cap to vinyl siding or greenhouse coverings to prevent heated exhaust air from damaging those materials. The thin-wall collar is also used needed when venting through walls less than 4 1/2″ thick. It is compatible with Williams DV14, DV22, and DV30 model heaters.
Williams Thin Wall Collar Installation Manual
