Riller & Fount Penny Open Back Dress in Olive. - size 3 / L (also in ) Riller & Fount Penny Open Back Dress in Olive. - size 3 / L (also in ) 95% rayon 5% spandex. Unlined. Lace-up back closure. Built-in bottoms. RILL-WD644. SM17 PEMNS. Back to basics this fall with Riller & Fount. Simple silhouettes and dramatic colors are perfect for any season.