Speed Sand 90 is a device designed to quickly and efficiently create accurate ninety-degree angles while sanding new drywall. The device may be modular and/or a non-modular. The non-modular version may comprise two main parts: a replacement pad and a tool portion (a perpendicularly-angled mounting beam and manipulator securer). The replacement pad may be a ninety-degree sponge with two aggregated sides. The tool portion of the device may comprise plastic or other suitable durable material. A universal ball joint, designed to accept any standard corner flushing handle, can be located at the center-back portion of the tool. The replacement pad may attach to the perpendicularly-angled mounting beam with adhesive material. The modular version may comprise slidably-removably-attachable wings having leading and trailing edges providing that the sanding device can be efficiently and effectively used in conjunction with an abrasive sponge to sand inside corners.