 The Invisible Condom , developed at <unk> <unk> in <unk> , Canada , is a gel that <unk> upon increased temperature after insertion into the <unk> or <unk> . In the lab , it has been shown to effectively block HIV and herpes <unk> virus . The barrier breaks down and <unk> after several hours . As of 2005 , the invisible condom is in the clinical trial phase , and has not yet been approved for use . 
