No, not for sending ahead. Buffer is probably a misleading term. Modern electronic keyers track if you've pressed the opposite key while the current element is completing. The HA-1 does not. So if you send (for instance) a 'N' character DAH followed by DIT and hit and release the DIT before the DAH has completed, it will be lost. So characters that have DAH-DIT or DAH-DIT-DAH can turn into DAH or DAH-DAH if your hasty with your thumb. A modern keyer will not lose the DIT because it's tracking keypresses even while an element is being sent. The HA-1 wakes up anew after every element to see what the operator has in store for it. Iambic Mode B actually tracks squeeze keying to buffer the extra-opposite element after you've let go. You either love or hate that mode.