Olofly (US): Birthday Cake | OG Kush | Zkittlez Cactus Labs Six Shooter D9o $37.99 The unparalleled simplicity and versatility of Birthday Cake | OG Kush | Zkittlez Cactus Labs Six Shooter D9o is unrivaled. The 6 grams of premium delta-9o distillate (commonly known as THC-O) in this disposable vape pen is distributed among the 3 strains of your choice.