Long fullness with a gathered wrist joins a stronger upper curve to a looser course below in this close front. The sleeves look sheer and gather at the wrists. Bow-like details accompany their shape. Vertical lines organise the warmer-looking pale bodice, while the complete hem lies outside the frame. The route from upper arm to ending is therefore clearer for an initial comparison than the complete lower silhouette. Keep that distinction when choosing the feature you want from the reference.
Decide which part appeals. Do you want greater upper volume, the longer loose surface or the gathered lower boundary? Compare those questions in turn on the actual candidate. Let hands hang normally first, then bring them in front of the body. Observe where the surface arranges itself beside the hand.
Obtain matching side and rear views when assessing an offer. The visible surface cannot confirm a particular fabric or warmth. If shortening is needed, discuss fullness distribution above the ending too. A suitable length should be assessed in relation to the desired loose form, rather than only as a measurement detached from the rest of the sleeve.