In Stock. 45 Day Lowest Price - 100% Satisfaction Guarantee. The Garrison AG-300 is setting a new standard for guitars in its price range. The Griffiths Active Top Brace replaces all the guitars top braces and bridge plate with a single, glass-fibre unit. Compare a Garrison AG series to any other guitar in its price point from any other manufacturer. You will not be able to deny the difference our technology makes.