All of our black rubber stoppers are laboratory grade. Each is marked on top with the size number for easy identification.
These rubber stoppers contain a high percentage of pure rubber and are low in free sulfur. The stopper composition ensures resiliency and pliability over a long period and will withstand laboratory conditions without hardening.
The upper working temperature of these black rubber stoppers is 212°F.
Contents of this set...
- (2 ea.) 1-hole #0 (NC-0922)
- (2 ea.) Solid #0 (NC-0950)
- (2 ea.) 1-hole #00 (NC-0965)
- (2 ea.) Solid #00 (NC-0968)
- (2 ea.) Solid #000 (NC-0969)