I'm not familiar with a brand called "Allarallvr," but rectangular sunglasses are a popular style that can complement various face shapes and outfits. Here are some general features and characteristics you might expect from rectangular sunglasses:

1. Shape: Rectangular sunglasses typically have a shape that's wider than it is tall, with angular or slightly rounded corners. This shape often suits square, heart-shaped, or oval face structures.

2. Frame Material: They can come in various frame materials such as plastic, acetate, metal, or a combination of materials, offering different levels of durability and aesthetics.

3. Lens Types: Rectangular sunglasses may feature different types of lenses, like polarized lenses for glare reduction, mirrored lenses for style, or UV-protective lenses for eye safety.

4. Color Variations: These sunglasses might come in a range of colors and patterns for both frames and lenses, catering to different preferences and styles.

5. Versatility: Rectangular sunglasses are known for their versatility, often blending well with casual, sporty, or more formal attire.

If "Allarallvr" is a specific brand, checking their product description or website can provide more detailed information about the features, materials, and specific styles they offer in their rectangular sunglasses. Ultimately, these sunglasses can offer both fashion and functionality, providing eye protection while adding a stylish touch to your look.

The description "Women 90s Retro Trendy Y2K Classical Vintage Square" seems to refer to a style of sunglasses that draw inspiration from the fashion trends of the 1990s and early 2000s (often referred to as Y2K fashion). Here are some features you might expect from this style:

1. Square Shape: These sunglasses typically have a square or slightly rectangular frame shape, which was a popular style during the 90s and Y2K era.

2. Vintage Design: The sunglasses may feature design elements reminiscent of vintage styles, such as thick frames, bold colors, or unique patterns.

3. Trendy and Retro: These sunglasses often combine a retro aesthetic with current trends, creating a fashionable and eye-catching accessory.

4. Variety of Colors: They might come in various colors and finishes, including vibrant hues or translucent frames that were iconic during the Y2K era.

5. UV Protection: Like most modern sunglasses, they're likely to offer UV protection to shield the eyes from harmful sun rays.

This style of sunglasses tends to be bold, expressive, and a nod to the nostalgic fashion trends of the past. They can be a fun and stylish accessory, perfect for adding a statement piece to an outfit or embracing a vintage-inspired look.