With the 'Hyper' mod the Rust Box is even more versatile
Take the standard Rust Box and enter a mod for more output power: this is very briefly what the the Hyper mod does.  Therefore, the Hyper Rust Box shares all its features with the Rust Box: controls, tone, dynamics, character, everything.  Plus, it will be capable of way more dB's. The Hyper mode is activated by means of a selector switch, flick it off and you're back with a standard Rust Box pedal.

Why more power?
Well, for one thing you might as well be into blasting everything that comes after the Rust Box, including your amp's input section and your ears. The Hyper mod makes some serious dB's available for when output power is never enough.  It's worth noting here that the internal gain structure of the Rust Box is not changed by the Hyper mod. Instead, you're simply getting more of what you already have available with the standard Rust Box.

But don’t let the extra power push you to using your Rust Box always to the limit.  One of the things I like most about the Hyper mod is that it opens up new sonic territories.  Especially when using the Rust Box as a clean booster.  It’s nice to take advantage of the totally transparent sonic character of the Rust Box, together with the possibility to fine-tune the eq with the Rust Box Baxandall tone shaping circuit, to kick the front end of your amp with some extra gain.

Disclaimer
Dino’s Guitars is not responsible for damage to your hearing and/ or your equipment that an incautious use of the Hyper Rust Box pedal might induce (i.e. if you’re into frying your amp, speakers and ears, it’s none of our business).  And to answer your question: yes, it's that loud!