Dental dams (or dams) are flat sheets of latex that are placed over the vagina or anus to act as a barrier to prevent STIs passing from person to person. Most dams are made of latex, but latex-free options are available if you are allergic Dental dams are an effective protection against STIs if they are used properly: Here are our top tips: Before using, check that dams are in date, and that the package hasn’t been ripped or damaged – never us an out of date dam or one with signs of damage Only use dams that have the kite mark on the packaging – this shows that the product is of a high quality and safe to use Never open the pack using your teeth or with scissors as this can damage the dental dam and beware of sharp nails and jewellery Use a water-based lube with a dam – no baby oil or Vaseline! After use, dispose of dams in a bin (not a toilet) and never reuse Dams are available for free for most under-25s from GPs, sexual health clinics and most pharmacies in Highland. If you are under 16 and want free dams, you may be asked a few questions to make sure that you are not at risk of harm, and that you understand how to use them correctly, but the service is confidential.