The flag of Trinidad and Tobago has an aspect ratio of 3:5. It consists of three main elements: a red field, a black diagonal stripe with white borders, and two white-edged black stripes that meet at the corners of the fly.

Colors:

1. Red (Pantone 186 C): HEX #CE1126, RGB (206, 17, 38)
2. White: HEX #FFFFFF, RGB (255, 255, 255)
3. Black: HEX #000000, RGB (0, 0, 0)

Geometric properties and measurements:

1. The red field covers the entire flag.
2. The black diagonal stripe starts at the upper hoist corner and ends at the lower fly corner, dividing the flag into two equal right triangles.
3. Each white border flanking the black diagonal stripe is 1/30th of the flag's width.
4. The black diagonal stripe itself is 1/15th of the flag's width.
5. Two white-edged black stripes are positioned adjacent to the flag's top and bottom edges, starting from the hoist side and meeting the black diagonal stripe at a 90-degree angle.
6. Each white edge of these two black stripes is 1/60th of the flag's width.
7. The black stripes themselves are 1/30th of the flag's width.