Refillable cartridge is a cost-effective and environmentally friendly option for vapers who want to use their preferred oils without constantly purchasing new cartridges. Here are some of the best refillable cartridge available:

1. Flacko Jodye Oil Tank: Designed by A$AP Rocky and handmade by Kandypens, this cartridge can hold 0.5 mL of cannabis oil and features gold trim with a sleek mouthpiece. It connects to any 510 thread battery .

2. SPRK Ceramic 3 Cartridge: A budget-friendly option with a leak-resistant TruCeramic core for great airflow. It's the third iteration of PCKT's ceramic cart, known for its cleanliness and durability .

3. Kandypens Special-K Oil Tank: Compatible with any 510 thread battery, this tank can hold up to a gram of oil. It's designed for durability and ease of use .

4. Linx Hermes 3 Atomizer: This atomizer uses top-tier ceramic heating technology for rich vapor and is constructed from medical-grade stainless steel. It's available in half and full-gram options.

5. SPRK FLO 510: Designed for thick weed oils, this refillable cartridge has a dual ceramic core and a unique coil design for quick absorption and longevity. It's also leak-resistant .

6. Kandypens Rose Gold Glass Tank: A sophisticated option with seamless airflow, handmade from high-quality glass and metal, and designed for repeated use .

When choosing a refillable cartridge, look for well-made coils that can handle multiple fillings and stand up to higher voltages. It's also important to ensure that the cartridge is compatible with your vape pen and that you use the correct type of oil for the refillable cartridge. Always practice proper care and maintenance to extend the life of your refillable cartridge.