Nowadays a lot of spare parts originated from Thailand already. Even my Vios brake pad original is Made in Thai. They claimed its Japan but god knows la. The one from Thais dont have the groove. Groove usage, Im not sure but most will say that it serve as an indicator of brake wear. If groove gone, time to change. Braking wise not a problem. Its better than Made in Malaysia one as a lot of Toyota owner complaining about local made brake pads too soft cant bite well. Not only that, it also create much more brake dust.