Discontinued line, and Shimano no longer offer a square-taper bottom bracket of this quality level. So grab one while there's still stock available!

The Bicycle Depot Technical Top Tip: If replacing a Shimano bottom bracket, check that the old one is the correct length before disassembly, that way you'll know for sure what axle length to buy. If unsure of the axle length and type you need, consult a professional bicycle mechanic.