• Lowpass and bandpass modes
• Self oscillation
• Rare russian op-amps used
• Input protection against overvoltage

If you decide an product is not suitable within 14 days of delivery, you can return it to us for a replacement or refund. Returns must be unused and in their original, undamaged packaging.

Some items are excluded from our money back guarantee:
- Computer software that has been unsealed or registered
- Any item that comes directly into contact with the nose, ears or mouth

To arrange a return, just contact our customer service department on 020 7424 2800 or via our customer support form.