2.5mm x 25 core flexible" cable likely refers to a 2.5mm2 size, but the "25 core" part of the query is unusual; if it were a 2-core or 3-core flexible cable, it would be used for appliance power, lighting circuits, and wiring in homes or offices. If it is a SY cable, "25 core" could indicate a large number of control wires, but the mention of the steel braid suggests an SY cable, not a standard flex cable.