K3NG open source Arduino CW keyer with WinKey support.
KIT contains all parts and laser engraved case. SMD parts are presoldered on the PCB.
Easy to build. 

https://github.com/ok1cdj/OpenCWKeyerMK2

Dimensions 50x58x24 mm.

Features

■ CW speed adjustable from 1 to 999 WPM

■ Programming and interfacing via USB port (“command line interface”)

■ PTT output with configurable lead, tail, and hang times

■ 2 memories with macros

■ Serial numbers

■ CW keyboard (via a terminal server program like Putty or the Arduino Serial program)

■ Speed potentiometer (speed also adjustable with commands)

■ QRSS and HSCW

■ Beacon / Fox mode

■ Iambic A and B

■ Straight key mode

■ Ultimatic mode

■ Bug mode

■ Paddle reverse

■ Farnsworth Timing

■ Adjustable frequency sidetone

■ Sidetone disable

■ Command mode for using the paddle to change settings, program memories, etc.

■ Keying Compensation

■ Dah to Dit Ratio adjustment

■ Weighting

■ Callsign receive practice

■ Send practice

■ Memory stacking

■ Logging and Contest Program Interfacing via K1EL Winkey 1.0 and 2.0 interface protocol emulation ■ “Dead Operator Watchdog”

■ Autospace

■ Wordspace Adjustment

■ Pre-configured and Custom Prosigns

■ Non-volatile storage of most settings

■ Modular code design allowing selection of features and easy code modification

■ Non-English Character Support