Streck offers Sperm-Chex and Sperm-Chex Post VC sperm count controls for fertility diagnosis. Sperm-Chex is an FDA-cleared, two-level sperm count control that contains stabilized sperm cells (not latex beads). Sperm-Chex Post VC is a positive/negative control developed to monitor post vasectomy sperm counts and contains actual sperm. Both products are packaged in plastic micro-tubes with screw top caps and are stable for 42 days open-vial, and 12 months closed-vial.