The ABB 1SFA899311R1312 is a PSTHM-312/18 thyristor unit designed for use with the PSTX softstarter series. This is the power switching element — the thyristor stack — that the PSTX controls to ramp motor voltage during start and stop. If you are sourcing this for a PSTX softstarter that needs a replacement thyristor module, this is the factory-matched part.
The thyristor unit is RoHS compliant per EU Directive 2011/65/EU and Amendment 2015/863. It falls outside WEEE scope (product not in WEEE scope, B2B classification). ABB also provides a Toxic Substances Control Act (TSCA) declaration and a Conflict Minerals Reporting Template (CMRT) for this order code — documentation that quality and compliance teams typically require for incoming inspection and audit trails.