At the moment, the smallest non sound is indeed the CT Elektronik Dcx77z at 7.5x5x1.8 mm, but it’s difficult to find these days. Easier to find and also very good is the D&H PD05A at 8x5.2x2.5 mm. Smallest sound decoder is without any doubt the Zimo MS500 at 14x10x2.6 mm.
Marc