After visiting the site, I found this information. "Once dissolved it creates a gel coating which contains a highly efficient spermicide that kills sperm on contact for 3 hours. VCF reaches itâs maximum protection after 15 minutes and stays active for 3 hours after insertion." I don't know if there is enough spermicide in one square of film to kill the sperm in two ejaculations, however. Because of terms of service rules, I cannot include the link to the website but I will send you a private message with the company's contact information.