There are total 4 electric guitars created by ESP Company for this collaboration. Two feature Sonic the Hedgehog, and the other two feature Shadow the Hedgehog illustrated on the body.
ESP will take orders for these Sonic the Hedgehog & Shadow the Hedgehog guitars from July 13, 2016 to June 30, 2017. It will take 4 to 6 months to get delivered after ordering.
The first game of Sonic the Hedgehog series was released on June 23, 1991, while Shadow the Hedgehog first appeared in Sonic Adventure 2, released in 2001. So 2016 is the 25th anniversary of the franchise and the 15th anniversary of Shadow the Hedgehog.
