The Shimano S70C are 70 mm long brake pads w/ Cartridge pads for XT V-brake up to BR-M770.
They are also suitable for LX, Deore, Alivio & many other v-brakes.
The very good performance & durability in dry conditions is slightly reduced in wet & muddy conditions.
On the other hand, the S70C is extremely gentle on aluminum rims.