Black Rubber Stopper #2 1-hole (5mm). Top diam. is .787"(20mm). Bottom diam. is .630"(16mm). Height is .984"(25mm).
Approximately 58.1 per pound.
Forensics Lab Supply Number 3731105.
Formerly Grau-Hall Corporation dba Grau-Hall Scientific.
NOTE: Unlike some inexpensive imported products, these stoppers are made to standard size and hardness specifications.