RV slow rise roller shades typically rely on spring tension to hold the shade in place rather than a dedicated latching mechanism. The stop spring controls the slow-rise and tension, allowing the shade to retract smoothly. If your shade is not staying down, it usually means the spring tension is insufficient. To fix this, try re-tensioning the spring by winding it several more turns before reinstalling the shade. Also, ensure the shade is installed level and the mounting brackets are secure, as uneven installation can cause premature retraction. Most Irvine brand RV roller shades do not include a mechanical latch to lock the shade down; instead, the spring tension alone holds it. If your older shade model had a latch, it may be a different design or brand. For replacement parts, the 1.25" Irvine replacement slow rise spring is compatible with premium RV roller shades and can be purchased online. If you can provide your shade model or photos, further assistance or alternative solutions can be recommended.