Based on this product's specifications, here are some alternatives and similar models
Intercable ICR16V Butt Connector Straight Steel Inner Diameter 5.5 mm Outer Diameter 8.5 mm Length 35 mm
Summary description:
Intercable ICR16V straight butt connector designed for secure electrical installations and wire joining. Made of steel with an inner diameter of 5.5 mm, outer diameter of 8.5 mm, and a length of 35 mm. This reliable terminal ensures efficient electrical conductivity and stable connections in professional wiring applications. Supplied in a convenient pack of 50 pieces.