Gonz said:This is a more permanent solution
But the "rapex" has raised fears amongst anti-rape activists that it could escalate violence against women.
"If a victim is wearing such a device it may enrage the attacker further and possibly result in more harm being caused," said Sam Waterhouse, advocacy co-ordinator for Rape Crisis.
Other critics say the condom is mediaeval and barbaric -- an accusation Ehlers says should be directed rather at the act of rape.
"This is not about vengeance ... but the deed, that is what I hate," she said
Ehlers said the "rapex" hooks onto the rapist's skin, allowing the victim time to escape and helping to identify perpetrators.
"He will obviously be too pre-occupied at this stage," she told reporters in Kleinmond, a small holiday village about 100km (60 miles) east of Cape Town. "I promise you he is going to be too sore. He will go straight to hospital."