What’s the closest thing on Robinhood to buying 4-week t-bills from treasurydirect?

I get that it’s not possible to _directly_ buy a tbill on Robinhood, but I know there are options. There are so many bond etc ETFs on there and I can’t seem to tell which one of them most closely just tracks the 4-week tbill as searching “T-bill” yields a lot of results. For example, the 1-3 month Bloomberg T-bill… well which rate am I getting the 1 or 3 month? I want the 4-week, not whatever else.