The Positional Cooling Platform Device (PCPD, known as the ‘CryoKit’) is a 3-D printable device that supports reproducible cryopreservation with standard cooling rates (5 to 35°C/min). The CryoKit accommodates French straws (0.25 and 0.5-mL) and cryopreservation vials (0.5 and 2-mL). Efforts in development of germplasm repositories to preserve genetic resources of aquatic species are impeded globally by a lack of standardized, inexpensive, reproducible, and portable cryopreservation technologies. The CryoKit (v2.4.7) can be used with a standard Styrofoam container that holds liquid nitrogen for on-site sperm cryopreservation for aquatic species and is distributed as open hardware. Detailed instructions are provided https://3d.nih.gov/entries/3DPX-021194