Thia is a multi-site, randomised 2-period cross-over trial comparing five uses of a 61 mm width synthetic nitrile male condom with five uses of a 61 mm width standard latex male condom.

A sequential randomised 2-period cross-over trial comparing five uses of a 61 mm width synthetic nitrile male condom with five uses of a 61 mm width standard latex male condom. Each couple will be asked to use five synthetic nitrile condoms, and five latex control male condoms in a randomised order. Couples will complete a Condom Use Report after each condom use. Function, safety, and acceptability will be assessed at each of two follow-up visits conducted after using each set of five condoms. The trial will enrol up to 300 couples, anticipating that at least 255 couples will complete the study. Half of the couples (150) will be enrolled in Durban, South Africa and half (150) enrolled in California USA.

Inclusion Criteria:

1. Be between the ages of 18 and 45 years (inclusive);
2. Be literate (able to read a newspaper or letter easily);
3. Have been in an exclusive (monogamous) sexual relationship with partner for at least 3 months; and intend to continue to be an exclusive (monogamous) sexual relationship with their spouse or partner while participating in this research study;
4. Be sexually active (defined as having at least one vaginal coital act per week);
5. Willing to give informed consent;
6. Willing to complete the male condom coital use reports;
7. Willing to use the study condoms as directed;
8. Agree to use only the study lubricant provided;
9. Agree to only use the study condoms sequentially during time of participation
10. Willing to adhere to the follow-up schedule and all study procedures;
11. Willing to provide research study staff with an address, phone number or other locator information while participating in the study;
12. Willing to participate in the study for the duration of 10 condom uses (approximately 2-3 months);
13. Willing to provide photo identification and/or have fingerprint scan to exclude co-enrolment in other research projects;
14. Female partner using hormonal or other non-barrier contraception (e.g. OCs, injectable, implant, Intrauterine device (IUD), or have had a tubal sterilization) or male partner vasectomised;
15. Agree to return any unopened condoms;
16. Male partner willing to ejaculate during vaginal intercourse;
17. Male partner willing to hold on to the condom ring when withdrawing the erect penis after sexual intercourse;
18. Agree to not bring study condoms in contact with genital or oral piercing jewelry
19. EAH: Both partners have valid personal email and operable mobile phones;
20. Former participant in Karex02 Study: male partner measures at least 118 mm in girth of erect penis.
21. Agree that information provided in Karex02 study may be used and combined with the information in this study

Exclusion Criteria:

1. Female partner is pregnant or desires to become pregnant during the time of the research study;
2. Either partner is known to be HIV positive (based on self report [EAH] or documented HIV-negative test result within past two months;
3. Self-reported history of recurrent sexually transmitted infection (e.g. gonorrhea, syphilis, Chlamydia);
4. Male partner has known erectile or ejaculatory dysfunction;
5. Either partner has genital piercing jewelry, uses genital beading or uses sex toys, drugs, medications or non-study devices that can affect sexual performance;
6. Either partner has known sensitivities or allergies to latex, synthetic nitrile, vaginal/sexual lubricants or lubricants used on condoms;
7. Either partner reports symptoms of STI (EAH) or has observable evidence of STI as determined through syndromic diagnosis and vaginal/penile examination (MRU);
8. Either partner is currently participating in another condom study;
9. Either partner is a past or current employee of Essential Access Health, University of the Witwatersrand, or Karex;
10. Either partner is a sex worker.

Each product will be labeled with a randomly generated code.