Cats (lb) Package color mg per tube Potency (mg/mL) Administered volume (mL) Up to 5 Mauve 15 mg 60 0.25 5.1–15 Blue 45 mg 60 0.75 15.1–22 Taupe 60 mg 60 1.0 For cats over 22 lbs use the appropriate combination of tubes. Dogs (lb) Package color mg per tube Potency (mg/mL) Administered volume (mL) Up to 5 Mauve 15 mg 60 0.25 5.1–10 Purple 30 mg 120 0.25 10.1–20 Brown 60 mg 120 0.5 20.1–40 Red 120 mg 120 1.0 40.1–85 Teal 240 mg 120 2.0 85.1–130 Plum 360 mg 120 3.0 For dogs over 130 lbs use the appropriate combination of tubes.

They are identical products re-branded for different countries. The manufacturer (Pfizer) sets different prices on their brands for different markets.

There's no difference apart from dosages

Stronghold protects against American dog ticks.

They are identical products re-branded for different countries. Both are from the same manufacturer with the same ingredient and dosage. All genuine.