PERT, FLEX, PRELL, SUAVE, and BRECK are all popular shampoo brands. PERT is a 4-letter brand that has been around since the 1970s and is known for its gentle cleansing formula. FLEX is also a 4-letter brand that is known for its moisturizing properties. PRELL is a 5-letter brand that has been around since the 1940s and is known for its deep cleaning capabilities. SUAVE is a 5-letter brand that is known for its affordable price point and variety of scents. Finally, BRECK is a 5-letter brand that has been around since the 1950s and is known for its luxurious feel.