This is the Blue Tune Pipe Coupler and Exhaust Deflector set from Traxxas.

This is a Stock part for:

1/10 Revo 3.3 (5308)
1/10 Revo 3.3 (5309)
1/10 Jato 3.3 (5507)
1/10 Slayer Pro 4x4 (5907)

This is an Optional part for:

1/10 Slayer 2wd (5908)
 
Features:

• Silicone construction
• Blue in color
• Connects Exhaust Header and the Tune Pipe.  

Includes:

One (1) Tune Pipe Coupler 
One (1) Exhaust Deflector
One (1) Short Tie-Strap 
Two (2) Long Tie-Straps 
 
Specifications:

Coupler Length: 24mm (.95") 
Coupler Inner Diameter, Large: 14mm (.55") 
Coupler Inner Diameter, Small: 13mm (.51") 
Coupler Outer Diameter, Large: 25mm (.98") 
Coupler Outer Diameter, Small: 22mm (.87") 
Deflector Length: 61mm (2.4") 
Deflector Inner Diameter, Small: 8mm (.32") 
Deflector Inner Diameter, Large: 10mm (.40") 
Deflector Outer Diameter, Small: 11mm (.44") 
Deflector Outer Diameter, Large: 14mm (.55")