Waterproof seal
The heat shrink sleeve with melt adhesive creates a strong, waterproof barrier that protects connections from moisture and corrosion.
- Free shipping
- 14-day easy returns
- Secure checkout
- Quality guaranteed
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Why customers love it
Waterproof splices that seal, solder, and protect in one step
These heat shrink wire connectors create a watertight, corrosion-resistant splice for automotive, marine, and DIY electrical projects—no separate soldering required.
- Waterproof heat shrink sleeve with melt adhesive blocks moisture and corrosion
- Pre-installed solder ring melts during heating for a solid, conductive joint
- Tinned copper terminals deliver superior conductivity and oxidation resistance
- Transparent sleeve lets you visually confirm the connection before and after heating
- Heat shrink, seal, and solder in one simple step for faster, cleaner installations
Why choose these connectors
No separate soldering
A pre-installed solder ring melts during heating to form a solid, conductive joint, eliminating the need for extra flux or solder.
Easy visual inspection
The transparent sleeve allows you to confirm the connection is properly made before and after heating.
Superior conductivity
Tinned copper terminals ensure optimal electrical performance and resist oxidation over time.
Setup
How to use
No electrician, no wiring, no fuss.
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Insert wires
Place stripped wire ends into the connector, ensuring they meet at the solder ring.
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Apply heat
Use a heat source to shrink the sleeve; the pre-installed solder ring melts to form a solid joint.
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Seal and inspect
The melt adhesive creates a waterproof seal—check through the transparent sleeve to confirm the connection.
Specs
The details that matter
Built to last outdoors, season after season.
- Quantity
- 50PCS
- Model
- SST21
- Wire Gauge
- AWG22-18
- Type
- Butt Electrical Splice
- Terminal Material
- Tinned copper
Comparison
Why choose these over traditional connectors
Not all products in this category are built the same.
Feature
SmartPicksWorld
Typical alternative
Moisture protection
Waterproof heat shrink sleeve with melt adhesive seals out moisture
May not seal moisture, risking corrosion
Soldering method
Pre-installed solder ring melts during heating—no separate solder or flux needed
Requires separate soldering or crimping tools
Inspection
Transparent sleeve allows visual confirmation of the joint
Opaque housing hides the connection from view
Our worry-free shopping promise
If your order arrives damaged, defective, or not as described, contact us within 14 days and we will make it right with a replacement or refund.
Frequently asked questions
Everything you might want to know before you order.
What wire gauge does this SST21 model support?
This SST21 model is designed for AWG22-18 wire, making it suitable for a range of automotive, marine, and DIY electrical applications.
How does the waterproof seal work?
The heat shrink sleeve contains a melt adhesive that activates during heating, creating a strong, waterproof seal that protects the connection from moisture and corrosion.
Do I need separate solder or flux?
No—each connector has a pre-installed solder ring that melts during heating, forming a solid, conductive joint without the need for separate soldering materials.
Can I inspect the connection before heating?
Yes, the transparent sleeve allows you to visually confirm the wire placement and connection before and after heating.
What material are the terminals made of?
The terminals are made of tinned copper, which provides superior conductivity and resistance to oxidation.
Shipping & returns
Shipping
- Delivers to United States (based on your selected country/region).
- Estimated delivery: 3–15 business days after dispatch.
- Shipping cost: Free.
Returns
You can request a return within 14 days after delivery. Standard returns have a €4.00 EUR (approximately $4.66 USD) flat-rate return shipping fee, deducted from your refund. Return shipping is free for items that arrived damaged, defective, or incorrect. Items should be unused and in original packaging where possible. Contact us before sending anything back.