PPG Delfleet Evolution F3519 Weak Blue Black (often listed as F3519X3.5L or ZF35193) is a specialized tinting toner used in the Delfleet Evolution commercial coatings system. 
Key Information & Features:
Color: Weak Blue Black.
System: Delfleet Evolution (a high-performance, premium paint system for commercial vehicles and fleet maintenance).
Purpose: Primarily used as a tinter/toner in color matching for commercial vehicle refinishing.
Volume: Commonly available in 3.5 Litre (3.5L) or 1 Gallon containers, depending on region.
Performance: Part of a system designed for high gloss, superior durability, and ease of application without sagging on rivets. 
Safety & Handling:
Hazards: F3519 is flammable liquid and vapor (H226), can cause drowsiness or dizziness (H336), and is harmful to aquatic life with long-lasting effects (H412