ST-XL (Hallite 520) wipers are direct replacements for ST or D wipers.
Designed to have interference in the seal housing groove and has a secondary lip. The secondary sealing lip located behind the primary sealing lip improves stability of the seal in the gland.
The inner dynamic lip is shorter and more robust to improve sealing and compression set characteristics over conventional, symmetrical U-seals.
The seal can be considered for use in heavy-duty applications when used with a suitable full depth back-up ring. The sealing lips are precision trimmed at an angle to give optimal rod sealing performance.