Barely used, bought it for a project and I never finis it.

The AGB/918-2 is a buffer preamp that features adjustable gain which allows you to boost the input signal up to 12dB while maintaining flat frequency response. It is less than ½ the size of a 9-volt battery making it ideal for instruments with limited cavity space. The AGB/918-2 provides a strong output signal and isolation from external equipment that may otherwise adversely affect pickup tone. It is often used to make a passive instrument active with very little effort. With only 4 wires to connect – power, ground, input, and output – it is a simple way to add flexibility and power to your guitar or bass with active or passive pickups.
The AGDB/918-2 provides 2 independent buffers in the same space as the AGB/918-2. This is great for separately boosting 2 pickups into either a simple dual-volume setup or even into an EQ preamp. When you have 2 passive pickups with low output, you can easily boost and isolate them with the AGDB/918-2 – effectively making them active pickups.
Like all of our preamps, the AGB and AGDB are internally shielded to reject electromagnetic noise and include internal filters to block AM and FM radio on the inputs. Bartolini set the standard of fully sealing the sensitive electronics. We use professional double tin plated pure copper wire with durable semi-rigid insulation.
Either preamp can be used with either a single 9-volt battery (9-volt operation) or two 9-volt batteries wired in series (18-volt operation) for 6dB extra headroom with no tonal change. Both versions delivery clear and transparent sound with extremely low distortion.