IF you are throwing tennis balls for your dog:

Chuckit! Ultra Rubber Ball, Large | Dog Toys

$7.95

Chewy.com

(1k+)

 You are less likely to pull a muscle when you throw tennis balls for your dog on the beach or on a field if you use a Chuck-it. I have both a blue one and an orange one but I find a smaller chuck it fits tennis balls better for throwing.

Chuckit! Sport Launcher, Color Varies, 12M

$6.95

Chewy.com