FrSky's XSR 2.4GHz receiver features 16ch ACCST, with S-Bus and CPPM. This little guy is physically smaller and lighter weight than the X4R receiver. Making it great for mini race quads!

Compatibility
FrSky X-series Module & X9D & X9DP &X9E & X12S in D16 mode. （XSR does not work with D-series Module） The LBT version of XSR receiver only works with FrSky D16-LBT Mode.

 
Features 

• Smart Port enabled, realizing two-way full duplex transmission.
• S-BUS output. CPPM output.
• Lighter weight and physically smaller than X4R.
• More number of channels: 1~16ch from SBUS channel,1~8ch from CPPM Channel.
• FrSky XSR 2.4GHz 16CH ACCST Receiver w/ S-Bus & CPPM

Specs 

• Dimension: 26*19.2*5mm(L x W x H)
• Antenna Length: 90mm
• Weight : 3.8g
• Operating Voltage Range: 4.0~10V
• Operating Current: 100mA @5V
• Number of Channels: XSR - 16Ch(1~16ch from SBUS Channel,1~8ch from CPPM Channel)

Download 

• Download the FrSky XSR manual.