Envelope filter is in excellent condition. Works properly and fully tested Manufacturer: The EBS BassIQ Triple Envelope Filter delivers big, bad, and luscious funk bass sounds. It gives you 3 different modes to choose from: Hi-Q, Up, and Down. Up mode is the classic envelope filter sound while Down, as you'd guess, is the opposite; it reverses the attack of the filter. Hi-Q delivers auto-wah type effects that react to your playing touch. Threshold and Attack knobs let you get it on with the right amount of funk. EBS bass effect pedals are designed to preserve the entire frequency range of your bass signal, use noiseless FET switching, are suitable both for studio and live use, feature robust construction, and are easy to use.