Closed transferring equipment, including carboy caps, canes, tubing, CO2 tanks and accessories, kegs, regulators, air filters, and various keg connectors. All the equipment you'd need for a closed transfer and pressurized fermentation.
If there's anything I've learned from the talented brewers I've grown up around (truthfully), it's that once fermentation is a go, oxygen is the enemy. Some brewers even claim that a positive pressure fermentation leads to better tasting beer. I'll leave it to you folks, the real experts, to determine the truth in that. But in the meantime, here's a bunch of equipment for closed transferring. Just, you know, let me know how it goes. Oh and send me some beer. You know, "for science".