Another variation is an inflatable or stackable ring design, which can limit the depth of penetration to protect the receiving partner from pain or discomfort.
anotheR vAriatIOn Is An inFLAtAblE or staCKAblE riNG desIGN, which can liMIt the dEPTH of peNetRaTiOn To protEct THE rECeivINg parTNer froM pAin or diScoMFOrt.