When caulking underneath ShingleVent II installed on architectural shingles what type of caulk should be used?

A tri-polymer type sealant should be used when applying it under a ridge vent that is installed on top of architectural shingles.

The installation instructions for ShingleVent II call for a sealant underneath the vent on architectural shingles because the dragon's tooth on many arch shingles creates a naturally occurring gap between the bottom of the vent and shingle. Applying a sealant protects against possible weather infiltration. Sealant should be applied directly under the external baffle on the ridge vent. Care must be taken to get a seal between the ridge vent and the architectural shingle without blocking the vent's weep holes. The weep holes are designed to allow water to run out from inside the ridge vent if necessary, such as when rain falls straight down. A tri-polymer type sealant should be used, one which maintains its flexibility when exposed to the weather elements encountered by the ridge vent. Most roofing cements will breakdown or crack when exposed to UV, thus losing the waterproof seal under the ridge vent. There really is no need to apply sealant between the 4-foot pieces of ridge vent. The ridge cap shingles cover the gaps between the ridge vent pieces. Assuming that the space left between the ridge vent pieces is 1/8 as recommended, it is the same width as the louvers on the sides of the ridge vent -- and thus will not present a problem.