Umbra Knock Knock Door Hangers, Surf Blue Knock Knock Door Hangers by Umbra Constructed of rubber Holds two 3 inch by 3 inch photos or sayings; fits any standard door knob; sentiment, greetings or photo display in one Measures 4 Inch by 8 Inch by 1/2 inch Designed by Sung Wook Park Knock Knock Door Hangers by Umbra Holds two 3 inch by 3 inch photos or sayings; fits any standard door knob; sentiment, greetings or photo display in one Measures 4 Inch by 8 Inch by 1/2 inch Designed by Sung Wook Park