This is a classic Polo Ralph Lauren waist-length work style jacket from the late 80s-90s. Made in Singapore, it's red cotton twill with a front metal zipper, waist length, long sleeve with a short collar. Unlined. Embroidered horse & rider logo on the left chest. The color is actually a deeper red than is showing in these pix.
 
Pre-owned, used; in good condition with no noted flaws but the elastic on the cuffs isn't super tight anymore.
 
Marked as size L; please read the actual garment measurements given next--
Pit to pit- 22 1/2" measured across the chest between the underarm seams
Elastic waist- 36" up to 40" gently stretched
Center front length- 20 1/2" along the length of the zipper
Sleeve length- 23 1/2"
Back width- approx. 16"