Round rubber plugs rubber cover silicone end caps

Silicone end caps cover a round feature through a profile that fits around its outside, while an inserted round plug engages a bore. These closure arrangements use different mating dimensions even when their visible top faces look similar. Identify the selected arrangement before comparing a cap size with the component being closed.

For an external cap, check the diameter along the full engagement length and any rim or shoulder it must pass. The cap needs enough depth to remain positioned without its top stopping against an unintended obstruction. Leave practical access to remove it without repeatedly stretching one small portion of the edge.

Fit the closure evenly and examine the perimeter for a rolled lip or tilted seating. The mating surface should be free of burrs and trapped particles. Any required leakage or pressure performance must be evaluated in the complete joint with the selected material formulation. During reuse, inspect the internal contact area, since wear there can change retention while the broad outside face still appears intact.

Material options

Custom silicone compound; formulation and geometry developed together.

Hardness selection

Silicone options: 20–80 Shore A. Leave practical access to remove it without repeatedly stretching one small portion of the edge.

Custom geometry

For an external cap, check the diameter along the full engagement length and any rim or shoulder it must pass.

Fit evaluation

Fit the closure evenly and examine the perimeter for a rolled lip or tilted seating.

Color & OEM

Custom colors; OEM identification positioned outside closure contact surfaces.

Photos illustrate structure or material appearance only. Silicone end caps cover a round feature through a profile that fits around its outside, while an inserted round plug engages a bore. ETOL directly manufactures custom-shaped silicone and rubber parts to your requirements.