DELANO, Calif. (KGET) — The wireless signal at Kern Valley State Prison must be pretty strong. A number of inmates apparently want to use it.

On July 1, staff at the Delano prison seized boxes shipped through Fed Ex and found 85 cellphones inside, according to a recent court filing.

The phones were shipped in six boxes addressed to three inmates who, the filing says, could have substantially improved their position behind bars. Investigators said the phones “have an approximate prison value of $425,000.”

It is a misdemeanor to own an unauthorized cellphone in prison.