Ink Blue Koi Water Pipe with Ice Pinch and Removable Downstem
Understanding Downstem Sizes
Downstems have two measurements: joint size (where it connects to your bong, typically 14mm or 18mm) and length (measured in inches or millimeters). To find your size, measure from the bottom of the ground joint to where you want the stem to end in the water—usually 1" above the base.
Types of Downstems
- Diffused Downstems: Multiple slits for enhanced filtration
- Open-End Downstems: Simple, unrestricted airflow
- Showerhead Downstems: Maximum diffusion with multiple holes
- Colored/Worked Downstems: Functional art for custom builds
When to Replace Your Downstem
Replace your downstem if you notice chips, cracks, or if diffusion slots become clogged beyond cleaning. Upgrading to a better diffused downstem is one of the easiest ways to improve your bong's performance.
Replacement Downstems — FAQ
What does a downstem do?
The downstem is the glass tube that connects your bowl to your bong, extending into the water. Its purpose is to pull smoke below the waterline, creating bubbles that filter and cool the smoke before it reaches you. Diffused downstems (with slits or holes) multiply the bubble count for smoother hits.
How do I measure a downstem?
Measure from the bottom edge of the ground-glass joint (where it meets your bong) to the tip of the stem in millimeters. Common sizes: 2.5", 3", 3.5", 4", 4.5", 5". The tip should sit 1/4"–1/2" below your waterline for optimal bubbling without drag.
What joint sizes do downstems come in?
Standard sizes are 14mm and 18mm on both ends. You'll see listings like '14mm/18mm' — meaning 18mm joint (fits bong) and 14mm bowl socket (fits your bowl). Always verify both ends match your bong joint and bowl before buying.
Diffused vs. non-diffused — which is better?
Diffused downstems (slitted or showerhead) break smoke into many small bubbles for better filtration and cooler hits. Non-diffused are simpler but harsher. For water pipes without additional percolators, a diffused downstem is the biggest upgrade you can make.