There are many different types of dIs available on the market, so it really depends on what you're looking for in a DI box. If you're primarily looking for a way to improve your bass guitar's tone, you may want to consider investing in a unit that uses larger transformers, like the Whirlwind DI mentioned earlier. However, if you just want something to plug into your bass guitar and not particularly concerned about the sound quality, a simple standard DI unit will work just fine.