Based on this product's specifications, here are some alternatives and similar models
Simet electric heating brick KE-LTF12-4.0 – model KE-LTF12-4.0
Summary description:
Simet KOSTKA ELEKTRYCZNA KE-LTF12-4.0 is an electric heating brick designed for integration into heating systems and construction elements. Provided model KE-LTF12-4.0 delivers electric heating functionality from the manufacturer Simet. Suitable for retrofitting or new installations where a compact electric heating element is required. Check compatibility with your system before installation.