Delock Cable Micro USB type B male angled> USB 2.0-A female OTG 11 cm (Accessories)
I have this adapter for my Asus MeMo HD risen 7. It works! There is this, however, some important things: Since the HD7 unfortunately does not provide 5 V power supply at the Micro-USB, you need a Y-cable (eg Delock Adapter Power USB cable 2x USB Y-c