Black Rubber Stopper #6-½ 1-hole (5mm). Top diam. is 1.339"(34mm). Bottom diam. is 1.063"(27mm). Height is .984"(25mm).
Approximately 18.8 per pound.
Forensics Lab Supply Number 3731111.
Formerly Grau-Hall Corporation dba Grau-Hall Scientific.
NOTE: Unlike some inexpensive imported products, these stoppers are made to standard size and hardness specifications.