The latest development from Spektrum sees them incorporate a two-channel receiver inside a digital servo. The new two-in-one item features a metal-geared servo housing a DSMR receiver for an incredibly compact package. The ingenious S6240RX has a built-in SR2010 receiver all inside a servo case that is shorter than many standard 1:10-scale servos. This makes it ideal for applications where space is at a premium like some 2WD buggies for example whilst the other benefit is a weight reduction.
Source: Spektrum RC
