A transfer has three costs: a deposit fee, a conversion fee and a send fee. Grey shows all three, and the shilling amount your recipient receives, before you confirm. That makes the rate only one part of what a USD to KES transfer really costs.
On a $500 transfer funded by ACH, the deposit fee is 0.8 percent (minimum $2, maximum $10), about $4. The conversion fee is 1 percent, capped at $6, so $5 here. The send fee is shown separately, and the exact shilling amount for a USD to KES transfer is shown before you confirm. Your recipient can receive shillings in an M-Pesa wallet linked to a Safaricom number, or in an account at Equity Bank, KCB Bank, Co-operative Bank, NCBA or Standard Chartered Kenya.