All of our dumbbells are sold as pairs. If you only received one dumbbell, a small percentage of our orders get separated during the transit process from our warehouse to you. The rest of your order is likely still in transit. The tracking number that you receive from our system will be the "Parent" tracking number for your entire order. Each box will have it's own individual tracking number. To track each box go to FedEx.com type in the "parent" tracking number and scroll down to see the status of each box.