Mini-Kits EFHW 49:1 Autotransformer Kit.  This Kit uses the Fair-rite 2643251002 Toroid for high efficiency with a rating of 100 Watts CW ( FT8 ) and an estimated rating of >300 Watts SSB.  The Kit includes everything to construct your own Transformer.

Included In the Kit:  1 x 2643251002 Toroid, 1 x D9020 ABS Enclosure, 1.1m x 1mm Enamelled copper wire, Hookup wire for internal connections, 8 x Cable ties, 2x Cable Tie mounts and screws, 2 x M5 Eyelet Hooks, nuts and washers ( Stainless Steel 304 ),  4 x M5.3 Eyelet crimp terminals, 1 x 100pF 500v Silver Mica Capacitor, Your choice of BNC or UHF Female connector.

You will require the following which is not included in the Kit.  Wire for the Antenna, >20Metre length for a 40m to 10m band version, or >40m length for a 80m to 10m band version.  A counterpoise will also be required on the ground connection of the Autotransformer.  For a counterpoise it is suggested that the coax feedline is used and choked off at distance along the feedline using 6 to 8 turns of the coaxial cable through a FT240-43 Toroid.  The recommended distance  from the Autotransformer is 2 metres for a 40-10m version, or 4 metres for a 80-10m version.  The choke provides a reduction of noise from the Radio end appearing at the Antenna, and RF from the Antenna coming down the feedline to the Radio.