Based on this product's specifications, here are some alternatives and similar models
Drill Bit Extension 450 mm Dedra DED1500-45 with SDS+ Shank
Summary description:
Extension for core drill bits, 450 mm length, Dedra model DED1500-45 with SDS+ shank. Designed to extend reach when using diamond or core drilling crowns on rotary hammer drills with SDS+ chuck. Provides additional length for drilling deeper holes or reaching confined areas; suitable for masonry, concrete and construction tasks where extended bit reach is required.