SNUG PLUG系列4號塞，直徑4.4cm，比3號大0.8cm，多重70g。大部份人不能直接吞，要少量擴張或完全放鬆才能放入，算是中階選項。
整個系列尺寸齊全，由左至右，從小到大，順序排列。
頂部是易於進入圓錐形設計，軀干位置卻是稀有的直身柱體形，如此直徑均一，容易量度，可以準確符合開發中的最佳尺寸，不會強行撐開門戶。頸部只有一厘米粗，不會撐大門口，而且可因應姿勢彎曲，在站立時、坐下時還是行走時減低異物感。
每個型號內建負重，會小幅度郁動。重量是訓練入口的緊緻度和咬合力的必要原素。平常行走時使用會被帶動而在直腸管道中上下滑動。而這種微刺激會令肛門括約肌反射性收縮，就像舉啞鈴一樣有鍛練效果。
If you or your partner have been flirting with advanced anal play, there's nothing more satisfying than the Snug Plug 4.
Weighing a hefty 257 grams with an insertable size of 5.2 inches, the Snug Plug 4 provides erotic stimulation along the anal canal, prostate, and G-spot. It does everything like its predecessors and more!
If you've landed on the Snug Plug 4 for the first time, we recommend checking out the Snug Plug 1, Snug Plug 2, and Snug Plug 3 to learn which weighted butt plug would be best suited to your needs.
When using large butt plugs, always apply plenty of lube and don't bite off more than you can chew. Scroll down to learn why sex educators are calling the Snug Plug 4 as the best sex toy for anal stimulation.
★ Best Sex Toy for Traveling — Allure
★ Best Beginner Butt Plug — Cosmo Lab of Sexcellence
★ Best Gift to Give Women — NYLON
★ Best Sex Toy to Buy Your Boyfriend — Women's Health
| 1號 | 2號 | 3號 | 4號 | 5號 |
| 直徑： 2.2cm | 3.1cm | 3.6cm | 4.4cm | 5.1cm |
| 重量：55g | 114g | 180g | 257g | 350g |
| 插入長度：8.6cm | 11cm | 12cm | 13.3cm | 14cm |
