Final Lap is a feature in the Mario Kart series in which the player has to do one more circuit of the entire course before officially finishing the course. The sign is always held by Lakitu. From Mario Kart 7 onward, the final lap sign says 3/3 with the numerator in yellow.
Super Mario Kart
This marks the debut of the Final Lap feature. The sign in this game has black and white checkered marks on the side and Final Lap in gold writing.
Mario Kart 64
This time around, Lakitu's holding the sign with two hands. The background is in blue and the text is in white.
Mario Kart: Super Circuit
Lakitu holds the sign the same way he did in Mario Kart 64, except the Final Lap sign has a grayish-black background with the Final in white and the Lap in red.
Mario Kart: Double Dash!!
Lakitu adopted its current format of using a fishing rod to hold the sign up. It is still horizontal but has white text, a black background and the white text flashes black to white, black to white, etc.
Mario Kart DS
The sign looks like a briefcase now, with white edges and text, all capitalized, but rather than the horizontal format, it has Final on top and Lap on bottom.
Mario Kart Wii
The sign looks the same with the colors, but is back to horizontal and capitalized. Only difference is, there is a line drawn on the bottom.
Mario Kart 7
Mario Kart 7 is the first game not to use the Final Lap sign. Instead, there is a gray top, black and white checkered edges and it says 3/3, with the numerator in bold yellow and a messy line through the two numbers. The E3 2010 demo however still used the Final Lap sign.
Mario Kart 8 / Mario Kart 8 Deluxe
The sign around the 3/3 looks very detailed, with a second layer overlapping. Mario Kart 8 and Deluxe use the 3/3 method, same design as their predecessor.