真空继电器由于在真空中只有非常少的气体分子，这使得真空中不容易产生电弧，在理想的状态下，真空有可能达到每0.1毫米10000V的介电强度。另外，由于没有空气的存在，真空中触点不会氧化，因此真空型继电器的接触电阻较小而且较稳定。特别适合应用于射频场合。GT16、GT21、GTH3、GT8、GT10、GT12、GTH3、GTH5、PT22、PTXX、GT8、GT16、GT24、GTH8、GT65、PT22、PTXX、GT80、GT50 GTVAC issued a new 15kV and high load switching relay. The new GT18 is the same size as GTVAC's GT8 vacuum relay that is used for RF applications and lower current switching, their GT2 vacuum relay with copper contacts for high current RF carry applications, and their GT15 SF6 gas filled relay for high in-rush current "make" applications. According to Jim Lanum, product manager at GTVAC, "the GT18 fills out our line of Single Pole Double Throw (SPDT) 15kV relays making it easy for customers to select the smallest and best relay for their specific application".