The Spenco Men's Knee Support insole provides semi-rigid stability that increases foot balance, helping to guide the foot through proper movement. Increased motion control allows the muscles and tendons in the feet and legs to function more efficiently and reduces pain and discomfort in feet, ankles and knees. The semi-rigid stability cradle was engineered to provide medium arch support, deep heel cupping and comfort through the stride. Forefoot perforations increase air flow for more breathability. This insole is intended to fit men's shoe sizes 7-13 and may be trimmed as needed for a true custom fit. To trim, simply remove the existing insole from your shoe, line it up with your new Spenco Knee Support insole as a guide and trace with a ballpoint pen. Carefully cut with a sharp pair of scissors, then insert into your shoe with the top side up.