The Topping Ext 90 Input Extender lets you instantaneously multiply the number of connections your Topping pre-amplifier can accommodate. Designed for desktop use & small scale by nature Topping pre-amps generally come with one set of RCA & Balanced XLR inputs each. Now via a simple connection the Ext 90 extension increases that overall amount to four XLR & two RCA stereo inputs. Compatible with the Topping Pre 90 pre-amplifier & Topping A90 Discrete headphone amp effortlessly convert your desktop setup into a multi-source audio solution.