Engineering (XCOM2)

Engineering and item purchases work a little different with young Miss Shen: main armor and weapons/subweapons only need to be purchased once to 'unlock' them (hence larger down payments of resources), upon which you have an unlimited supply that'll be auto-applied to all soldiers (in terms of internal logic, assume she made 6, enough for a full squad). The Proving Ground items are bought more traditionally, with a build time and a greater variety of material costs, such as the E.X.O. Suit armor, and the Spider suit, as well as item weapons like the special grenades.