Ruby Red Grapefruit Cocktail

"It's been too long! Who's ready for cocktail of the day ?!? Today I'm sharing a Ruby Red Grapefruit Cocktail! let's get shaking. Recipe from @eatingwell"
-- @sweetlifebake

Serves 4

1 1/2 cups fresh ruby red grapefruit juice
1 1/2 cups seltzer 
1/2 cup gin
2 tablespoons Campari

Grapefruit slices to garnish
Stir grapefruit juice, seltzer, gin and campari in a pitcher. Fill 4 glasses with ice and serve. Garnish with grapefruit slices.