These are similar to a hyperdrive, but with one significant difference: a transit generator shifts a ship into hyperspace and then…leaves it there. You will need to use the transit generator again to drop back to normal space.

A universe where transit generators are the standard for FTL travel assumes that hyperspace can be navigated like real space, using your starship's normal propulsion. Or it assumes that hyperspace has “currents”, that carry your ship along with it, without need for propulsion.

Transit generators are smaller than hyperdrives, for the simple reason that they don't provide any hyper thrust on their own. A generator can transit one tonne of ship for every 2kg of generator—so your transit generators will occupy 2% of the ship's total mass. They occupy one cubic meter per every 750 tonnes it can transit, but this space requirement is halved if the generator is located entirely externally. Mind you, external transit generators like this cannot be worked on from inside the ship. You have to land the ship, or go EVA, in order to fix it.

Transit generators are rather expensive, at ₠400 per tonne of ship to which they are fitted.