Welch Allyn HomeD-Ring Extra Small Cuff - 1700 Series Only

Is the extra large cuff directly compatible with the welch allyn home 1700 series bp monitor or is the adapter required to use the xl cuff every tim?

Is this needed for a 7yr old or will the included one work?

Can this cuff be used with other monitors? or does it connect to your phone?

What is a "D" ring ?