Features: 1.For BMW's suffer a common issue with the swirl flaps in the inlet manifold. The Screws holding the butterflies can come loose can cause severe damage to your engine. It's a well known issue that has been covered many times on the for BMW fo s & magazines. The easiest way to prevent this damage occurring to your engine is to replace these swirl flap bungs with these. 2.The swirl flaps are with poor design, they are prone to failure. When the swirl flap broke, the debris falls into the engine. Sticking in the valve port causing the piston to collide with the valve or falls into the cylinder itself and damaging the piston and the head. 3.blanks are manufactured from reinforced aluminum, that's designed for automotive use. Specification Suitable for BMW E87 E46 E60 E61 (4 cylinder) For BMW E30 E46 3 Series E46 03-06 320cd 330cd 5 Series E39 97-03 520d 525td 530d Color: Red + Silver Material: Aluminum + Silicone Package Contents: 4 * installed swirl flap 22mm 4 * square heterosexual ring 5 * round heterosexual circle Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.