The K7 Beer Equipment kit includes all the conveniences you get with the K3 kit, like an automatic pump-style siphon, an adhesive thermometer for the primary fermenter, and a full 27-page beginner's guide. But the K7 has a 7.8 gallon bucket and a 5 gallon glass carboy (contrast two, 6.5 gallon buckets in the K3). The 5 gallon carboy is perfect for secondary fermentation of standard 5 gallon batches, and the 7.8 gallon bucket allows more room for primary fermentation.
The K7 Beer Equipment Kit includes:
7.8 Gallon Bucket with Drilled & Grommeted Lid
5 Gallon Glass Carboy with Rubber Stopper
3-Piece Airlock (for Fermenting Bucket)
Adhesive Thermometer (for Fermenting Bucket)
Automatic Pump-style Siphon with 5' of flexible tubing