Red Hound Auto Stainless Steel Beverage Cup Drink Holder Drop in with Drain Marine Boat Car RV 1 Marine Grade Stainless Steel Cup Holder with drain Constructed of heavy duty marine grade stainless steel that is durable and made to last Cup holders are lab-tested for wet, salty conditions Inside of the cup holder has narrow and wide stages (to accommodate smaller drinks like cans and larger cups) Hole cutout required on boat or RV: 3-3/4". Inside diameter: 2-5/8" for small drinks (3-5/8" for larger drinks) Outside diameter (lip): 4-1/4". Height: 3-1/4" (4" with drain)