Thank you for submitting your item for appraisal. This appears to be a first half 20th century Double Comb-Back Windsor armchair marked at the underside with a manufacturer sign "NS within the silhouette of a chair", possibly Nichols & Stone. Fan back windsor chairs are quite common and they are being sold at auction on a regular basis. This double comb-back version is a rather rare sight. Latest auction results are within the price range listed. Retail prices are usually a little higher and can vary. There is no measurement for the sentimental value you might attach to the item.